In triangle ABC, ∠A = 90°. AD is the altitude to BC. If AB = 15 cm and AC = 20 cm, what is the length of AD?
Show answer & explanation
Correct answer: B
Explanation
∠A = 90°, AB = 15 cm, AC = 20 cm
According to the formula:
Hypotenuse (BC) = √(AB² + AC²)
Perpendicular AD = (AB × AC) / BC
BC = √(15² + 20²)
= √(225 + 400)
= √625
= 25
AD = (15 × 20) / 25 = 12 cm