2013 · Q92
In a right-angled triangle ABC, ∠C = 90° and CD is perpendicular to AB. If AB×CD = CA×CB, then 1/CD² is equal to
Elementary MathematicsGeometry
- A1/AB²−1/CA²
- B1/AB²−1/CB²
- C1/BC²+1/CA²
- D1/BC²−1/CA² if CA>CB
Explanation
1/CD²=1/AC²+1/BC². Answer C.