Dưới đây là đoạn tài liệu được trích trong BST Đề thi Olympic Tiếng Anh lớp 9 vòng 24 đề số 1 năm 2013:
Chọn câu trả lời tốt nhất cho những câu hỏi dưới đây.
1. AD // CB and cut by transversal AB. AC ⊥ CB. AB = 10, ∠DAB = 35°. Which of the following expressions could be used to determine the length of AC?
A. 10 cos55°
B. 10 sin55°
C. 10 cos35°
D. 10 tan35°
E. 10 cot35°
2. What is the area, in square inches, of the circle that is circumscribed about an equilateral triangle that has a perimeter of 36 inches?
A. 18π ≈ 56.55
B. 27π ≈ 84.82
C. 36π ≈ 113.10
D. 48π ≈ 150.80
E. 56π ≈ 175.93
3. The apothem (drawn from the center, perpendicular to a side) of a regular hexagon has a length of 6. What is the perimeter of the hexagon?
A. 2√3 ≈ 3.46
B. 4√3 ≈ 6.93
C. 8√3 ≈ 13.86
D. 12√3 ≈ 20.78
E. 24√3 ≈ 41.57
4. Trapezoid ABCD is inscribed in circle P. If AB ≌ BC ≌ CD and AP = 12, what is the measure of the median of the trapezoid?
5. First rotate the triangle bounded by the vertices (0, 0), (0, 5), (4, 0) about the origin 180°. Then, reflect the resulting image across the x-axis. What quadrant contains the final image of the triangle after both transformations?
A. quadrant I
B. quadrant II
C. quadrant III
D. quadrant IV
E. None of them
6. Theorem: A triangle has at most one obtuse angle. Eduardo is proving the theorem above by contradiction. He began by assuming that in ΔABC, ∠A and ∠B are both obtuse. Which theorem will Eduardo use to reach a contradiction?
A. If two angles of a triangle are equal, the sides opposite the angles are equal.
B. If two supplementary angles are equal, the angles each measure 90°.
C. The largest angle in a triangle is opposite the longest side.
D. The sum of the measures of the angles of a triangle is 180°.
E. In a triangle, the sum of any two sides is longer than the third side and the difference of any two sides is shorter than the third side.
Nhanh tay, tải miễn phí Đề thi Olympic Tiếng Anh lớp 9 vòng 24 đề số 1 năm 2013
này các em nhé. Chúc các em thành công!