Circle in Triangle

Geometry Level 2

There is a circle inscribed in a right angled triangle. The circle is touching all 3 sides of the triangle. The triangle has sides 3, 4 and 5.

What's is the radius of the circle?

1.5 2 0.5 1

1 solution

Henry U
Oct 25, 2018

The radius of the inscribed circle in a polygon with area $A$ and perimeter $u$ is $r = \frac {2A}{u}$ . In this case, we have $A = \frac {3 \cdot 4}{2} = 6$ and $u = 3 + 4 + 5 = 12$ , so $r = \frac {2 \cdot 6}{12} = 1$ .

Circle in Triangle

1 solution

0 pending reports