GMAT
题目
ABCD is a square, AD = 6, EB = 6 − 2b, the triangle is isosceles, and the probability that a randomly selected point in square ABCD will be in the shaded triangle is .
Quantity A
b
Quantity B
2
解析
已知：
ABCD 为正方形
EB = 6 - 2b，AD = 6
因此 AE = 2b
三角形面积 = (1/2) × 2b × 2b = 2b²
正方形面积 = 6² = 36
点落在三角形区域内的概率 = 2b² / 36 = 1/3（已知条件）
解得 b（A项）= √6 ≈ 2.44 > 2（B项）
选项 A 正确
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