## anonymous 5 years ago Can someone help me? If a sphere has a diameter of 26 units then what is the surface area of the sphere? A.) 507 π square units B.)1,352 π square units C.)2,929 π square units D.) 676 π sqaure units

1. anonymous

$A = 4 \pi r^2 = 4 \pi 13^2 = 676 \pi$

2. anonymous

You just posted this.. Don't repost.

3. anonymous

Did you find the surface area equation?

4. anonymous

@ muh4ha thanks so much :)

5. anonymous

no problem katie - but you rly should try and understand it, so you can do it on your own. Did you get, why I plugged in 13 ?

6. anonymous

ni can you explain?

7. anonymous

Because the 'r' in the Formula is the 'radius' of the sphere - that's the distance from the center to the surface. You are given the diameter - that's twice as much (same as when looking at a circle).. So another way of writing the formula would be: $A = 4 \pi ({d \over 2})^2$ okay? Did you get it? Any other questions?

8. anonymous

oh wow thanks so much :)

9. anonymous

you're welcome :) best thing to do, would be to try another example completely on your own and see if you can get it ;)