Question

Find the perimeter of the semi-circular region at leat one please

Answer 1

$\bf \textit{area of a circle}\\\\ A=\pi r^2\qquad r=radius\\\\ -------------------------------\\\\ 3)\\\\ \textit{since the diameter is 20, then the radius is half that}\\\\ A=\pi 10^2\implies A=100\pi \\\\\\ 4)\\\\ r=14\qquad \qquad A=14^2\pi \implies A=196\pi \\\\\\ 5)\\\\ \textit{since the diameter is 8, then the radius is half that}\\\\ A=\pi 4^2\implies A=16\pi \\\\ -------------------------------\\\\ \textit{circumference of a circle}\\\\ C=2\pi r$

$\bf -------------------------------\\\\ \textit{diameter is 5, so radius is 2.5 then}\\\\ \stackrel{\textit{circumference of the circle}}{2\pi 2.5}\implies 5\pi \qquad \qquad \stackrel{\textit{circumference of the semi-circle}}{\cfrac{5\pi }{2}} \\\\\\ 6)\\\\ \textit{diameter is 21, so radius is 10.5 then}\\\\ \stackrel{\textit{circumference of the circle}}{2\pi 10.5}\implies 21\pi \qquad \qquad \stackrel{\textit{circumference of the semi-circle}}{\cfrac{21\pi }{2}}$

Answer 2

6.) 15.7 because you would multiple 3.14 by the diameter of 5. Then divide by .5.<span />