Question

Find the radius and the circumference to the nearest hundredth when d ≈ 3.2 in. Use 3.14 for π

Answer 1

• The circumference is approximately 10.05 inches.

• The radius is approximately 1.6 inches.

Explanation:

Use the formula.

C = πd

C = π(3.2) The diameter is 3.2. Substitute 3.2 for d.

C ≈ 3.14(3.2) Substitute 3.14 for π.

C ≈ 10.05 Multiply.

Use the formula.

d = 2r The diameter of a circle is the same as 2 times the radius.

3.2 ≈ 2r The diameter is 3.2. Substitute 3.2 for d.

3.2/ 2 ≈ 2r /2

Divide both sides by two.

1.6 ≈ r

The circumference is approximately 10.05 inches.

The radius is approximately 1.6 inches.

Answer 2

well 2r=d so 2r=3.2in so r= 1.60 inch

circumference is 2
`\pi`r
so 2(3.14)(1.60) = 10.048 = 10.05in.