Respuesta :

The area of a circle is pie r squared. so you are going to want to find the area of both circles and then because the middle of the disk is empty space, you will subtract the middle area from the bigger area. 
first, find the radius. The radius is the diameter divided by 2. So it is 6cm for the big circle. Then in the area equation the radius is squared so you get 36cm and then to get the final area you multiply by pie. (i don't have a calculator with me sorry). 
next, you want to find the area of the smaller circle. Do the same process and use the equation. You should get 0.5625 times pie.
Then the last step is taking 36cm times pie divided by 0.5625 cm times pie and you get your answer

Area of the disk is equals to 111.375cm².

What is area?

" Area is defined as the total space occupied by any two dimensional object enclosed in it."

Formula used

Area of the circle = πr²

value of π = 22 / 7

r = radius of the circle

radius = diameter / 2

According to the question,

Given,

Diameter of the compact disk = 12cm

Substitute the value in the formula we get,

radius 'r₁' =12 / 2

               = 6cm

Area of the compact disk = π × (6)²

                                          = 36π cm²                                     ___(1)

Diameter of the hole = 1.5cm

Substitute the value in the formula we get,

radius 'r₁' =1.5 / 2

               = 0.75cm

Area of the hole in the middle of the disk = π × (0.75)²

                                                                     = 0.5625π cm²  _____(2)

From  (1) and (2) we get,

Area of the disk = Area of the compact disk - Area of the hole

                          = 36π - 0.5625π

                          = 35.4375π cm²

Substitute the value of π we get,

Area of the disk = 35.4375 × ( 22 / 7)

                           = 111.375 cm²

Hence, area of the disk is equals to 111.375cm².

Learn more about area here

https://brainly.com/question/27683633

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