Answer :

Given: Equilateral triangle of side 9 cm is inscribed in a circle.

**Construction:** Join OA, OB, OC and drop a perpendicular bisector from center O to BC.

Here,

Area (ΔABC) = 3× area (ΔOBC)

Area (ΔABC) = a^{2} = × 9^{2} =

Now,

Area (ΔOBC) = × AC × OD = × 9 × OD

We know that,

Area (ΔABC) = 3× area (ΔOBC)

= × 9 × OD

OD =

Now, in ΔODC

By Pythagoras theorem

OC^{2} = OD^{2} + DC^{2}

OC^{2} = ^{2} + ^{2}

OC^{2} = + = = 27

OC =

∴ Radius = OC =

Rate this question :

Prove that there RS Aggarwal & V Aggarwal - Mathematics

Number of circlesRD Sharma - Mathematics

In the given figuRS Aggarwal & V Aggarwal - Mathematics

In the given figuRS Aggarwal & V Aggarwal - Mathematics

The question consRS Aggarwal & V Aggarwal - Mathematics

In the given figuRS Aggarwal & V Aggarwal - Mathematics

In the given figuRS Aggarwal & V Aggarwal - Mathematics

In the given figuRS Aggarwal & V Aggarwal - Mathematics

In the give figurRS Aggarwal & V Aggarwal - Mathematics

Prove that an angRS Aggarwal & V Aggarwal - Mathematics