The lengths of the two sides forming the right angle of a right-angled triangle are 21 cm and 20 cm. What is the radius of the circle circumscribing the triangle?

Given,

The lengths of the two sides forming the right angle of a right-angled triangle are 21 cm and 20 cm.

Let the length of hypotenuse of the right-angled triangle = $$H$$

$$=$$> $$H^2=21^2+20^2$$

$$=$$> $$H^2=441+400$$

$$=$$> $$H^2=841$$

$$=$$> $$H=29$$ cm

We know that diameter of the circle circumscribing the right-angled triangle is equal to length of hypotenuse

$$=$$> Diameter of the circle = 29 cm

$$=$$> Radius of the circle = $$\frac{29}{2}$$ = 14.5 cm

Hence, the correct answer is Option D