Question

the perimeter of the figure below is 65.9 cm. find the length of the missing side. (note: diagram is not to scale)

Explanation:

Step1: Sum known side - lengths

$9.2 + 4.7+4.7 + 4.7+4.7+12+2.2+2.2 + 9.2$
$=(9.2\times2)+(4.7\times4)+12+(2.2\times2)$
$=18.4 + 18.8+12 + 4.4$
$=53.6$ (cm)

Step2: Find missing side - length

Let the missing side - length be $x$.
We know that perimeter $P = 65.9$ cm and $P=\text{sum of known sides}+x$.
So $x=65.9 - 53.6$
$x = 12.3$ (cm)

Answer:

$12.3$ cm