2021 · Q29
ABC is a triangle right angled at A and AD is perpendicular to BC. If BD = 8 cm and DC = 12.5 cm, then what is AD equal to?
Elementary MathematicsGeometry: Lines, Angles and Triangles
- A7.5 cm
- B8.5 cm
- C9 cm
- D10 cm
Explanation
In a right triangle, the altitude to the hypotenuse satisfies AD² = BD·DC (geometric mean). So AD² = 8·12.5 = 100, giving AD = 10 cm. Hence option D.