To have a surface area of 9π square units of a ball, what should be the radius (in units) of the ball?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 1.5.
The area of a ball = 9π square units
The area of a ball = Surface Area of the Sphere = 4πr², where r is the radius of the sphere.
⇒ Area = 4 ×πr² = 9π
⇒ r2 = 9/4
⇒ r = 3/2 = 1.5 units