In a right angled triangle ABC, the lengths of the sides containing the right angle are 5 cm and 12 cm respectively. A circle is inscribed in the triangle ABC. What is the radius of the circle (in cm)?
Answer & explanation
Correct answer: option 1
By Pythagoras's theorem
BC2 = AC2 + AB2
= BC2 = (5)2 + (12)2
= BC2 = (25 + 144)
= BC2 = 169
= BC = 13 cm
Radius of circle = \(\frac{(AC + AB - BC)}{2}\) = \(\frac{(12 + 5 - 13)}{2}\) = \(\frac{4}{2}\) = 2 cm