Question 10
Circle TheoremsAn isosceles triangle of sides 13cm, 13cm, 10cm is inscribed in a circle. What is the radius of the circle?
- A.71/24cm
- B.12cm
- C.8cm
- D.7cm
- E.69 cm.
Show the answer and explanation
Answer: A (71/24cm)
Explanation
The height to the 10cm side is √(13² − 5²) = 12cm, so the area is 60cm². The circumradius R = abc/(4 × area) = (13 × 13 × 10)/240 = 169/24 = 7 1/24cm.