Single correct option
A right-angled triangle has legs of length 20 cm and 21 cm. What is the radius of its inscribed circle?
- A. 7 cm
- B. 8 cm
- C. 5 cm
- D. 6 cm
Show answer and solution
Answer: (D) 6 cm
Hypotenuse = √(20² + 21²) = √(400 + 441) = √841 = 29.
For a right triangle, inradius r = (a + b − c)/2 = (20 + 21 − 29)/2 = 6 cm.
Check with r = Area/semi-perimeter = (210)/(35) = 6 ✓.
For a right triangle, inradius r = (a + b − c)/2 = (20 + 21 − 29)/2 = 6 cm.
Check with r = Area/semi-perimeter = (210)/(35) = 6 ✓.
Saved on this device. Sign in or create a free account to keep it on every device.