Question

Marti is filling a 10– inch diameter ball with sand to make a medicine ball that can be used for exercising. To determine if the medicine ball will be too heavy after it is completely full of sand, she did some research and found that there is approximately 100 pounds of sand per cubic foot. How heavy will the medicine ball be after it is filled with sand, rounded to the nearest pound? A.30 pounds B.58 pounds C.24 pounds D.83 pounds

Answer 1

Answer:

Option A. $30\ pounds$

Step-by-step explanation:

step 1

Find the volume of the sphere ( medicine ball)

The volume is equal to

$V=\frac{4}{3}\pi r^{3}$

we have

$r=10/2=5\ in$ ----> the radius is half the diameter

Convert inches to feet

Remember that

1 ft=12 in

$r=5\ in=5/12\ ft$

assume

$\pi=3.14$

substitute

$V=\frac{4}{3}(3.14)(5/12)^{3}$

$V=0.3029\ ft^{3}$

step 2

Find the weight of the ball

Multiply the volume in cubic foot by 100

$0.3029*100=30.29\ pounds$

Round to the nearest pound

$30.29=30\ pounds$