Question

A groundskeeper needs grass seed to cover a circular field 290 feet in diameter

A store sells 50 pins bags of grass seed. One pound of grass seed covers about 400 square feet of field.
What is the smallest number of bags the groundskeeper must buy to cover the circular field?

Answer 1

4 bags

Explanation:

We need to find the area of the circular field. To do this, we use the formula

A=piR^2 (pi multiplied by radius squared)

The radius is going to be 290/2 which is 145 which we plug into the equation.

A=pi145^2

The next step is to square 145, getting 21025. But now we need to multiply that by pi (3.14). We get 66018.5 as the answer.

Now we need to figure out how many square feet one bag can cover. To do this, we multiply 400 by 50 (because one pound can cover 400ft and one bag has 50 pounds). We get 20000 as the amount one bag of grass seed can cover. Now we need to divide 66018.5 by 20000. We get 3.300925. But the groundskeeper can't buy a decimal of a bag so we have to round up to 4 bags of grass seed.

Answer 2

165

Explanation:

First we need to find the area of the field, A = r^2 * pi

The radius is 290 / 2 = 145 feet

A = 145 * 145 * 3.14 = 66018.5 sqr feet

One bag covers 400 sqr feet

Divide the Area by 400 sqr feet to find number of bags needed.

66018.5 / 400 = 165

He will need at least 165 bags to cover the field