**Areas related to Circles ncert solutions Chapter 12 Exercise 12.3 Question 13**

**13.** In fig, a square OABC is inscribed in a quadrant OPBQ. If, OA=20 cm, find the area of the shaded region (Use ).

**Solution:**

Area of shaded region= Area of quadrant OPBQ of circle - Area of square OABC **(1)**

It is given that OABC is a square which means that which is angle of sector of circle.

Radius of Quadrant of circle =r= Diagonal of square = OB

And, Diagonal of square

**cm**

Area of Quadrant OPBQ {where r is the radius and is the angle of sector of circle.}

**(2)**

Area of square OABC=side x side=20 x 20=400 ** (3)**

Putting **(2)** and **(3)** in **(1)**. we get

Area of shaded portion