Question

The diagram shows two circles with the same centre. The radius of the smaller circle is 2cm and the diameter of the larger circle is 8cm. Find the exact value of the area.

hello pls help me with question and show full working out ty :)

Answer 1

Answer: 12π sq. cm.

Explanation:

To calculate the area of the shaded part, we will have to deduct the area of the smaller circle (s) from the area of the bigger circle(b).

Area b = π x 4^2

= 16π

Area s = π x 2^2

= 4π

Area of shaded part = 16π - 4π = 12π

Answer 2

`\boxed{Area = 12\pi cm^2}`

Explanation:

Area of larger circle:

=>
`\pi r^2`

Where r = 4

=>
`\pi (4)^2`

=>
`16\pi` cm²

Area of smaller circle:

=>
`\pi r^2`

Where r = 2

=>
`\pi (2)^2`

=>
`4\pi` cm²

Area of shaded part:

=>
`16\pi-4\pi`

=>
`12\pi` cm²