the diameter of a baloon is 30 ft how many square yards make it?

Question

need help!!!!!!!!!

Answer 1

I'm assuming that the ballon is spherical. I'm also assuming that when you ask for the square yards, you're asking for the surface area.

The expression for surface area of a sphere:
A = 4*Pi*(r^2), where r = radius

You're given the diameter, which is twice the radius:
d = 2*r
r = d/2

A = 4*Pi*(r^2)
A = 4*Pi*((d/2)^2)
A = Pi*(d^2)
A = Pi*(30ft^2)
A = 900*Pi square feet

Now you must convert from square feet to square yards. There are 9 square feet per square yard, so:
A = 100*Pi square yards

Note: You could have done the conversion from feet to yards at the outset (30 feet = 10 yards) and arrived at the same answer.

Answer 2

D = 10 yd
r = 5 yds
Surface Area = 4.π.r² = 100π = 314 yd²

Answer 3

assuming the balloon is a sphere:

SA = 4*pi*r^2
since d = 30ft; r = 15 ft ( 1 yd/3ft) = 5 yds

SA = 4*pi* (5)^2

SA = 100 pi sq. yd