Answer:
Step-by-step explanation:
Given
Find the length of HG
First, it should be noted that the displayed figure is a trapezium
<em>The area of a trapezium is calculated by multiplying the sum of parallel sides by half its height;</em>
In this case;
Substitute the values of Area, HE and EF
Divide both sides by 4
Subtract 12 from both sides
<em>Hence, the length of HG is 5mm</em>