A chord of a circle of radius 10 cm subtends a right angle at the centre. The length of the chord is
- 10 cm
- 5 (square root of 2) cm
- 20 cm
- 10 (square root of 2) cm
Show answer and solution
Correct answer: D. 10 (square root of 2) cm
1. Chord with central angle 90 degrees forms an isosceles right triangle with two radii as legs.
2. Chord squared = 10 squared + 10 squared = 200.
3. Chord = 10 (square root of 2) cm.
_Source: syllabus Mathematics, Ch 10 "Circles", §10.3_