The area of a shape is the amount of space it can occupy.
The value of r is 13
From the question (see attachment), we have:
[tex]\mathbf{A =176}[/tex] --- area of the shaded region
[tex]\mathbf{w = 2}[/tex] --- the width of the shaded region
The area of the complete circle would be:
[tex]\mathbf{A_1 =\pi (r + w)^2}[/tex]
The area of the small circle is:
[tex]\mathbf{A_2 =\pi r^2}[/tex]
So, the area of the shaded region is:
[tex]\mathbf{A = A_1 - A_2}[/tex]
Substitute known values
[tex]\mathbf{176 =\pi (r + w)^2 - \pi r^2 }[/tex]
Substitute 2 for w
[tex]\mathbf{176 =\pi (r + 2)^2 - \pi r^2 }[/tex]
Expand
[tex]\mathbf{176 =\pi (r^2 + 4r + 4) - \pi r^2 }[/tex]
Open brackets
[tex]\mathbf{176 =\pi r^2 + 4\pi r + 4\pi - \pi r^2 }[/tex]
Cancel out line terms
[tex]\mathbf{176 =4\pi r + 4\pi }[/tex]
Divide through by 4
[tex]\mathbf{44 =\pi r + \pi }[/tex]
Factor out pi
[tex]\mathbf{44 =\pi(r+ 1) }[/tex]
Divide through by pi
[tex]\mathbf{r + 1= \frac{44}{ \pi} }[/tex]
Substitute 22/7 for pi
[tex]\mathbf{r + 1= \frac{44}{ 22/7} }[/tex]
Using a calculator, we have
[tex]\mathbf{r + 1= 14}[/tex]
Solve for r
[tex]\mathbf{r= 14 -1}[/tex]
[tex]\mathbf{r= 13}[/tex]
Hence, the value of r is 13
Read more about areas of circles at:
https://brainly.com/question/23328170
