Đề kiểm tra Hình học Lớp 9 - Tiết 18 - Năm học 2008-2009

PhòNG GD & ĐT Yên dũng
Trường THCS ...........................................
Họ và tên:.........................................................
Lớp:............
 Bài kiểm tra hình 9 tiết 18
đề 1
 Thời gian làm bài: 45 phút
 Ngày ........... tháng 10 năm 2008
 Điểm Lời phê của giáo viên 
A- Phần trắc nghiệm khách quan:
Câu 1(1,5 điểm) Khoanh tròn chữ cái in hoa đứng trước kết quả đúng:
1. Cos N bằng:
 A. B. C. 
2. x bằng: 
 A. 4,8 B. 3,6 C. 2,4
3. Tg N bằng:
 A. B. C. 
Câu 2(1,5 điểm) Hãy ghép mỗi ý ở cột A với một ý ở cột B để được khẳng định đúng.
A
B
1. Bình phương mỗi cạnh góc vuông bằng
a. Tổng bình phương hai cạnh góc vuông
2. Bình phương đường cao ứng với cạnh huyền bằng
b. Tổng các nghịch đảo của bình phương hai cạnh góc vuông 
3. Tích hai cạnh góc vuông bằng
c. Tích của cạnh huyền và đường cao tương ứng
4. Nghịch đảo bình phương đường cao ứng với cạnh huyền bằng
d. Tích của cạnh huyền và hình chiếu của cạnh góc vuông đó trên cạnh huyền 
f. Tích hai hình chiếu của hai cạnh góc vuông trên cạnh huyền
Trả lời: 1-.......... 2- .......... 3- ............ 4- .........
Câu 3(1điểm) Điền đúng (Đ) hoặc sai (S) vào ô trống thích hợp:
 A. Sin 370 = Cos 630 B. Tg 540 > Tg 39050’
 C. Tg 380 < Sin 380 D. Sin2a + Cos2a = 1 (a là góc nhọn) 
 B-Phần tự luận:
Câu 4: (2điểm) Dựng góc nhọn a, biết tg a = 
Lời giải:
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Câu 5(4 điểm) Cho tam giác ABC vuông ở A đường cao AH. Biết AB = 3 cm và 
Tính BC, AC và 
Gọi E, F là chân đường vuông góc hạ từ H xuống AB và AC. Chứng minh rằng tứ giác AEHF là hình chữ nhật, từ đó suy ra EF2 = AE . AB
Tính diện tích tứ giác BEFC.
Lời giải:
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Câu 5(4 điểm) Cho tam giác ABC vuông ở A . Biết AB = 4 cm và BC = 8 cm
Tính AC ; ; 
Đường cao AH (H ẻ BC). Tính HB; HC
Từ H kẻ HE AB ( E ẻ AB); HK AC (Kẻ AC) Tính diện tích tứ giác AEHK.
Lời giải:
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Đáp án
Câu
ý
Nội dung
Điểm
1
1 - b
2 - f
3 - a
4 - d
0.25
0.25
0.25
0.25
2
A
B
C
D
Đ
S
S
Đ
0.25
0.25
0.25
0.25
3
1
2
3
C
B
C
0.25
0.25
0.25
4
-Dựng hình đúng
-Dựng góc vuông xOy. Lấy một đoạn thẳng làm đơn vị. Trên tia Ox lấy điểm A sao cho OA = 2, trên tia Oy lấy điểm B Sao cho OB = 3. 
-Ta có bằng góc a cần dựng
- Thật vậy Cotga = Cotg = = 
1
0,5
0,25
0,25
5
0,25
1
- Tính đúng BC = cm
0,5
- Tính đúng 
0,5
- Tính đúng 
0,25
2
-Tính đúng HB = 2 cm 
0,5
-Tính đúng HC = 6 cm
0,5
3
-Tính được HK
0,5
-Tính được HE
0,5
-Tính được StgAEHK
0,5