The sides of a cube measures 6.5cm. If the surface area of the cube is the same as a ball, what is the radius of the ball? Round to the nearest whole number.  Choose the correct choice from the following choices.
A) 9 B) 7 C) 4 D) 8 E) 6

Rationale: first calculate the surface area of the cube . the cube is made of 6 squares with the sides measuring 6.5 cm each . the surface area of 1 side of the cube is 42.25 cm . multiply the surface area of the 1 side by 6 will give you the cube ' s total surface area . the cubes surface area is 253.5 cm . now we know that the surface area of the ball is 253.5 cm . to find out the surface area of a sphere you need to square the radius , then multiply by pi , and multiply by the number 4 . going backwards to find the radius - you will need to dived the surface area by 4 . then divide by pi . then determine the square root of the answer . the radius is 4.460 . rounding to the nearest whole number the radius is 4 . the correct answer is ( c ) .
Answer: C