The perimeter of any polygon is the sum of the length of the outline sides
From the attached picture we can see
A polygon with 5 sides
The lengths of 4 sides are h cm
The length of the 5th side is 1.7 cm
To find its perimeter add the length of the 5 sides
[tex]h+h+h+h+1.7=P[/tex]Since the perimeter is given 10.5 cm, then
P = 10.5
Substitute P by 10.5 in the equation above
[tex]h+h+h+h+1.7=10.5[/tex]Add the like terms on the left side
[tex]\begin{gathered} (h+h+h+h)+1.7=10.5 \\ 4h+1.7=10.5 \end{gathered}[/tex]Subtract 1.7 from both sides
[tex]\begin{gathered} 4h+1.7-1.7=10.5-1.7 \\ 4h=8.8 \end{gathered}[/tex]Divide both sides by 4
[tex]\begin{gathered} \frac{4h}{4}=\frac{8.8}{4} \\ h=2.2 \end{gathered}[/tex]The value of h is 2.2 cm
The answer is a
We can check the answer by adding the 5 sides, the answer must be 10.5
[tex]\begin{gathered} 2.2+2.2+2.2+2.2+1.7= \\ 8.8+1.7= \\ 10.5\text{ cm} \end{gathered}[/tex]The answer is correct
