Question

Find the circumference and the area of a circle with radius 9cm.

Use the value 3.14 for pie , and do not round your answers. Be sure to include the correct units in your answers.

Answer 1

Circumference = 56.52 cm

Area = 254.34 cm^2

Explanation:

Finding the circumference (C):

The formula for the circumference of a circle is given by:

C = πd, where

• C is the circumference,
• and d is the diameter.

Finding the diameter (d) and the circumference (C):

• The diameter (d) is simply twice the radius (r).

Thus, we can find the diameter (d) by doubling the radius (r):

d = 2r

d = 2(9)

d = 18

Thus, the diameter of the circle is 18 cm.

Now we can find the circumference (C) by substituting 3.14 for π and 18 for d in the circle circumference formula:

C = 3.14(18)

C = 56.52

Thus, the circumference of the circle is 56.52 cm.

Finding the area (A):

The formula for the area of a circle is given by:

A = πr^2, where

• A is the area in units squared,
• and r is the radius.

We can find the area (A) by substituting 3.14 for π and 9 for r in the circle area formula:

A = 3.14(9)^2

A = 3.14(81)

A = 254.34

Thus, the area of the circle is 254.34 cm^2.