Question

Find the radius of the incircle of the right angled triangle whose sides measure $8,10$ and $12$ cm?

• A. $1.22$ cm
• B. $2.66$ cm
• C. $3.41$ cm
• D. $4.51$ cm

Answer 1

Answer: (B)

$2.66$ cm

Radius of the incircle $=$ $\frac{2\times \text{area of triangle}}{\text{sum of sides}}$
Area of triangle $=$ $\frac{1}{2}\times 8\times 10$ $=40$
Sum of the sides $=8+10+12=30$
Radius of the incircle $=$ $=\frac{2\left(\text{area of triangle}\right)}{\text{sum of sides}}$

$=\frac{2\times 40}{30}$
$=2.66$ cm.