The surface area of a sphere is 200 cm squared. If the radius were three times as large, what would the surface area be? Can you explain step by step?

Question

anonymous · Answer

just do width times hieght by 3

anonymous · Answer

wait never mind thats not right

anonymous · Answer

ummm ohhhhh chet idunno sorry steph

anonymous · Answer

surface aread of a sphere is given by $$4*\pi*r^2$$ you already have the area given.

anonymous · Answer

but at least yuh got a 1000 pple to help:)

anonymous · Answer

so $$200 = 4*\pi*r^2$$now what will happen if we had a radius 3x as large?

anonymous · Answer

see will this help http://www.kgbanswers.com/the-surface-area-of-a-sphere-is-200-cm-if-the-radius-were-3-times-as-large-what-would-the-surface-area-be/19885099

anonymous · Answer

$$200 = 4*\pi*r^{2}$$
$$r = \sqrt{\frac{ 200 }{ 4\pi }}$$
You have r, now multiply both sides by 3

$$3r = 3*\sqrt{\frac{ 200 }{ 4\pi }}$$

Put it back into the formula
$$(3*\sqrt{\frac{ 200 }{ 4\pi }})^{2}*4*\pi$$

anonymous · Answer

Thanks! I don't have a calculator with me, though. :/

anonymous · Answer

Nice one @DoritosHero good job :)