Substitute the given value for C into the circumference formula.
A
a
≈ 31.42 feet
B
b
≈ 4 feet
Practice makes perfect
a
We are given that Mr. Martinez is going to build the patio and we want to find the approximate circumference of this patio. Let's take a look at the given diagram.
Now we will recall that the circumference of a circle is two times the product of the radius of a circle and pi. In our exercise the radius of the patio is 3+ 2=5 feet.
C=2*5*π≈ 31.42
The circumference of the patio is approximately 31.42 feet.
b
In this part we are given that Mr. Martinez changes the plans so that the inner circle has a circumference of approximately 25 feet. To find the radius of the inner circle we will again use the circumference formula.
C=2Ï€ r
Let's substitute 25 for C and solve for r.
