The diagram shows a right angled triangle and a semi circle. PQ is the diameter of the semicircle. The perimeter of the whole diagam is... (a) 30 + 5pi (b)18 +6pi (c) 18 + 10pi

Using Pythagoras theorem in the right triangle, we get

PQ²=(13²-5²) cm²

⇒PQ²=144 cm²

⇒PQ=12 cm

Thus, diameter of the semi-circle = 12 cm

⇒Radius of the semi-circle = 6 cm.

Circumference of the semi-circle = cm

Thus, perimeter of the figure = (13 + 5 + 6)cm

   = (18 + 6)cm

The correct answer is option (B).