Question

find the perimeter of the window round to nearest tenth and then it says 20 cm i will send picture

Answer 1

The window is half a circle. We know that the perimeter of a full circle is:

$P=\pi D$

Where D is the diameter of the circle. Since we only have half of the circle the perimeter of our window will be:

$P=\frac{\pi D}{2}$

We need to find the diameter of the circle, from the picture we conclude the diameter is 40 cm (since the diameter is twice the radius).

Then our perimeter is:

$P=\frac{\pi\cdot40}{2}=62.8$

Therefore the perimeter of the window is 62.8 cm.