Question

Randy is designing a circular garden that is 18 feet in diameter. He is buying plastic edging that costs $1.50 per foot. He can only buy edging in whole-foot amounts. How much does it cost Randy to buy edging for his garden? Use 3.14 for pie.
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Answer 1

First we need to figure out the circumference of the gardening area. The circumference fell is the length around the circle. We can use the circumference formula:

2*pi*r or pi*d

Where r = radius and d=diameter

If you plug in the diameter of 18 ft you get:
18 * pi
= 56.55 ft

Since he can only buy whole foot amounts, we will round up to 57 ft, not down, because he can have a little extra, but can't be under the amount he needs.

Now if it cost $1.50 for every foot, we just multiply that by our footing

1.5 * 57 = $85.50