Question

Perimeter is 20cm. Can you find the missing side of the rectangle? Width is 6cm

Answer 1

The perimeter P of the rectagle is

$P=2W+2H$

where W is the width and H the height.

By substituting the given values into the perimeter, we have

$20=2\cdot6+2\cdot H$

which is equal to

$20=12+2W$

and we need to isolate W. This can be obtained by moving +12 to the left hand side as -12. It yields,

$\begin{gathered} 20-12=2W \\ 8=2W \end{gathered}$

and finally, W is given by

$\begin{gathered} 2W=8 \\ W=\frac{8}{2} \\ W=4 \end{gathered}$

That is, each of the remaining sides measure 4 cm