Question

A round shaped wall clock frame is made of a steel rod with length of 1.57m. calculate the radius,in m, of the frame.​

Answer 1

Check the picture below.

$\textit{Circumference of a circle}\\\\ C=2\pi r ~~ \begin{cases} r=radius\\[-0.5em] \hrulefill\\ C=1.57 \end{cases}\implies 1.57=2\pi r\implies \cfrac{1.57}{2\pi }=r\implies {\Large \begin{array}{llll} \stackrel{meters}{0.25}\approx r \end{array}}$