Question

Can someone check my answers please??

1. Find the surface area of a sphere with a radius of 4 inches.
a) 21 1/3*pi square inches
b) 64*pi square inches
c) 16*pi square inches
d) 256*pi square inches

My answer: B

2. Find the volume of a sphere with a radius of 3 inches.
a) 9*pi square in.
b) 27*pi square in.
c) 36*pi square in.
d) 81*pi square in.

My answer: C

Is this correct? Thanks for your help :)

Answer 1

Do you know the formulas for surface area and volume for spheres?

Answer 2

Yes, I worked out both of the problems. I'm 99% sure they are correct, I just wanted a little extra reassurance. :)

Answer 3

Ok, since the surface area formula is 4pr2, simpler form ( 4 x 3.14 x (radius x radius))

Question 1 would be 4 x 3.14 x 4^2 = 200.96
The answers it has with it have times pi so you would remove the 3.14 out so its 4 x 16, which is 64, so youre answer is right/

Question 2 is volume, which is 4/3 x p x r^3

Answers have pi in them again so remove the p out of the equation.
4/3 x 3^3 = 27

So your answer is wrong, Question 2 is B 27*pi

Answer 4

ohhh okay I understand. Thank you for helping! I'll redo the work and see if I come up with the same answers.