SSC CHSL 5 Mar 2018 Shift 1 Paper

Length of sides of triangle = 9, 12 and 15 cm
Clearly, it is aright angled triangle having ${\left(15\right)}^2={\left(9\right)}^2+{\left(12\right)}^2$ , where length of hypotenuse = 15 cm
Also, the circumcentre of a right angled triangle lies on its hypotenuse, thus circumradius = $\frac{1}{2}\times$ (hypotenuse)
= $\frac{1}{2}\times 15=7.5$cm