Họ tên: ……………………….
ĐỀ KIỂM TRA ĐỊNH KỲ LẦN 1
Môn: Hình học Lớp: 8
Ngày: 4/9/2015 Thời gian: 60 phút
Lời phê:
Bài 1: (4 điểm) Cho hình vẽ.
a) Tính độ dài đoạn AM; AN. (2 điểm)
b) Tính chu vi và diện tích tam giác AMN. (2 điểm)
Câu 2: (3 điểm) Cho hình vẽ.
Tính độ dài x, y ???
Hình 1 Hình 2
Bài 3:(3 điểm) Cho tam giác ABC vuông tại A. M,N,P lần lượt là trung điểm của AB, AC, BC.
a) Chứng minh rằng : Tứ giác BMNP là hình bình hành.
b) Chứng minh rằng : Tứ giác AMPN là hình chữ nhật.
c) Vẽ Q đối xứng với P qua N, R đối xứng với P qua M. Chứng minh rằng R,A,Q thẳng hàng.
Hết
A
P
N
M
12cm
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
...........................................................................................................................................................................................................
3
(vẽ hình đến câu b được 0,5 đ, Ghi GT,KL 0,5 đ)
a,Ta có M là trung điểm của AB
N là trung điểm của AC
1 điểm
1,5 điểm
O
4
3
2
1
A
B
C
R
Q
M
P
N
=>
1
2
MN BC MN BP
MN BP
MN BC


=>MBNP là hình bình hành
b) Ta có MP là đường trung bình của tam giác ABC => MP//AC => MP
AB
Ta có PN là đường trung bình của tam giác ABC => PN//AB => PN
AC
AMPN là hình chữ nhật (có 3 góc vuông)
c)Ta có
0
R
90
PM M
M
R đối xứng với P qua AB=>
12
(1)AA
Ta có
0
90
NP NQ
N
Q đối xứng với P qua AC=>
34
(2)AA
Ta có
00
1 2 3 4 2 3
2 2 2 2.90 180RAQ A A A A A A BAC
Vậy R,A,Q thẳng hàng
1,5 điểm
1 điểm