Determine the volume of the air inside the ball. Round to the nearest hundred.

Question

The circumference of an ncaa women's basketball is 29 inches, and the rubber coating is 3 / 4 thick. use the formula v = 4 / 3 × 3.14 × r, where V represents the volume and R is the radius of the inside of the ball.

Answer 1

Excellent explanation Michael.  One thing, though.  In the formula, Trevor, the radius must be cubed (r³ instead of r).  I'm sure it was just a typo.  But it can make a big difference.

Answer 2

The rubber coating makes the outside diameter.  The boundary inside is the inner diameter.  The distance between the inner and outer diameters is the thickness.  You want to use the inner radius.

 

 

Let's use the following equation to get what we need.

 

 

circumference = (outer diameter)π      ---->   to obtain outer diameter

 

outer diameter = 2(thickness) + inner diameter     ----->   to obtain inner diameter

 

Then, the inner radius is half the inner diameter.  Plug in that radius into the formula.