I have tried 11.97 and 12 and I keep getting the answer incorrect. I don\'t know

Question

I have tried 11.97 and 12 and I keep getting the answer incorrect. I don't know what the issue is? and if you can help me with the other two problems. thanks

The surface area of a basketball is equal to 1800 cm2. Determine the radius of the basketball.

The surface area of a basketball is equal to 1800 cm Determine the radius of the basketball Give your answer to the nearest cm 12cm Cm Submit My Answers Give Up Incorrect; Try Again; 2 attempts remaining Part C By what factor would you need to change the radius of a sphere, such that its volume increased by a factor of 7? Give your answer to two digits. AE Submit My Answers Give U Part D Suppose that a cylinder grows by only changing its radius (similar to one of the growth models in the Breathing Worms studio). If the radius of the cylinder doubles, by what factor will the volume of the cylinder increase by? AE

Explanation / Answer

B) let R is the radius of the ball.

we know, surface area, A = 4*pi*R^2

R = sqrt(A/(4*pi))

= sqrt(1800/(4*pi))

= 11.97 cm

= 12.0 cm (when we round to three significant figures) <<<<<------------Answer

= 12.00 cm (when we round to four significant figures) <<<<<------------Answer

C) we know,

V = (4/3)*pi*R^3

V' = (4/3)*pi*R'^3

V'/V = (R'/R)^3

7*V/V = (R'/R)^3

==> R'/R = 7^(1/3)

= 1.9 <<<<<------------Answer

D) Volume of cyllinder, V = pi*R^2*L

V' = pi*R'^2*L

= pi*(2*R)^2*L

= 4*pi*R^2*L

= 4*V

V'/V = 4 <<<<<------------Answer

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