0
You visited us 0 times! Enjoying our articles? Unlock Full Access!
Question

# An equilateral triangle of side 9 cm is inscribed in a circle. Find the radius of the circle.

A
33 cm
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
6 cm
No worries! Weâ€˜ve got your back. Try BYJUâ€˜S free classes today!
C
32 cm
No worries! Weâ€˜ve got your back. Try BYJUâ€˜S free classes today!
D
3 cm
No worries! Weâ€˜ve got your back. Try BYJUâ€˜S free classes today!
Open in App
Solution

## The correct option is A 3√3 cmLet triangle ABC be an equilateral triangle of side 9 cm, and AD be the median, where G is the centroid of the triangle that divides the median into 2:1. GD is perpendicular to BC. In the right-angled triangle ADB, AD2+DB2=AB2, where AB=9 cm and BD=4.5 cm. AD2+(92)2=92 AD2=92−(92)2 AD2=81−(814) AD=9√32cm Radius =23(AD)=23(9√32)=3√3cm

Suggest Corrections
3
Join BYJU'S Learning Program
Related Videos
Section Formula
MATHEMATICS
Watch in App
Explore more
Join BYJU'S Learning Program