Question

Find the Perimeter of the figure below, composed of a rectangle and a

semicircle. Round to the nearest tenths place.
4
6

Answer 1

Check the picture below.

so the rectangle's perimeter is pretty much just 4 + 6 + 6 = 16, now let's notice the semi-circle, is really just half of a circle whose diameter is 4, meaning that its radius is 2, so let's simply get the circumference of that semi-circle and add it to 16.

`\textit{circumference of a semi-circle}\\\\ C=\cfrac{1}{2}\cdot 2\pi r \begin{cases} r=radius\\[-0.5em] \hrulefill\\ r=2 \end{cases}\implies C=\cfrac{1}{2}\cdot 2\pi (2)\implies C=2\pi \\\\[-0.35em] ~\dotfill\\\\ \stackrel{Perimeter}{16~~ + ~~2\pi} ~~ \approx ~~ \text{\LARGE 22.3}`