The area of a sector of a circle with radius r, making an angle of x° at the centre is x

In the given figure, a square OABC has been inscribed in the quadrant OPBQ. If OA = 20 cm then the area of the shaded region is [take π = 3.14]

The diameter of a wheel is 84 cm. How many revolutions will it make to cover 792 m?

In the given figure, ABCD is a rectangle inscribed in a circle having length 8 cm and breadth 6 cm. If π = 3.14 then the area of the shaded region is

The circumference of a circle is 22 cm. Find its area. [Take π = 22/7]