Question

The radius of a circle is 7

centimeters. Find the area of the circle to the nearest tenth of a square centimeter. Is the exact area of the circle a rational or an irrational number? Is the approximate area you found a rational or an irrational number? Explain your answers.

What is the area of the circular item?

Answer 1

Answer: A = 153.9 cm^2 ; the exact area is an irrational number ; the approximate area is a rational number.

Explanation:

Our task is to find the area of the circle, given that:

• the radius is 7 cm

Apply the formula:

• 
  `\sf{A=\pi r^2}`

Where:

• A = area
• π = pi
• r = radius

Plug in 7 for r:

`\sf{A=\pi * 7^2}`

`\sf{A=49\pi}`

`\sf{A=153.9\;cm^2}\phantom{12} \textsf{(to the nearest tenth)}`

The exact area of the circle is an irrational number; when we multiplied a rational number, 49, times an irrational number, pi, we got an irrational number.

Answer 2

You take radius to the power of 2 and times that by 3.14