NET JRF PART - A : Questions and Solutions : NET JUNE-2013

NET JRF PART - A : Questions and Solutions:

NET JUNE-2013

1.) There is an equilateral triangle in the XY plane with its center at the origin. The distance of its vertices from the origin is 3.5 cm. The area of its circumcircle in cm ² is 

(a) 38.5 (b) 49 (c) 63.65 (d) 154 

Ans. : (a) 38.5 cm ² .

Solution: From the figure, we know that the radius of the circumcircle is 3.5 cm . 

The Area of the circumcircle = πr ² = π(3.5)(3.5) = 38.5 cm ² .