ABC is a right-angled triangle. If the lengths of two sides containing the right angle are 4 cm and 3 cm, the radius of its incircle is:

Correct option is C

Given:
ABC is a right-angled triangle.
Length of two sides containing the right angle (perpendicular and base) = 4 cm and 3 cm.
Formula Used:
Area of triangle = $$\frac 12$$​$$\times$$ base ​$$\times$$height​
Area of triangle = r $$\times$$ s (where 'r' is the inradius and 's' is the semi-perimeter)​
Pythagorean theorem: hypotenuse² = base² + perpendicular²
Semi-perimeter (s) =$$\frac {a+b+c}2$$​​
Solution:
Hypotenuse² = 3² + 4² = 9 + 16 = 25
Hypotenuse = 5 cm
Semi-perimeter=$$\frac{ (3 + 4 + 5) } 2 = \frac{12 } 2 =$$​ 6 cm

Area = $$\frac 12 \times$$​base $$\times$$​ height =$$\frac 12$$​ $$\times$$3 $$\times$$ 4 = 6 sq cm​​
Area = r$$\times$$ s​
6 = r$$\times$$ 6​
r = 1 cm
The radius of the incircle is 1 cm.