Question

http://prntscr.com/8u14q7

Answer 1

The radius is 2 cm. If you add up the four areas, we will have come full circle, you see. As the radius of the circle is 2 cm, we use the circle area formula is: \[A=\pi*r^{2}\rightarrow A=\pi*2^{2}\rightarrow A=4\pi\,\,cm^{2}.\]

Answer 2

Now, if you understand that "shaded portion" is is the inner rest of the figure, make the area of the square, less 4*pi, ou seja: \[A=4^2-4\pi\rightarrow A=(16-4\pi)\,cm^2.\]

Answer 3

please replace "ou seja" to "i.e", ok? ... and thanks for your trust

Answer 4

It's 14 cm not 4 cm.