Answer: 44 m
Step-by-step explanation:
Given
The area of the trapezium is [tex]A=480\ m^2[/tex]
Distance between parallel sides [tex]h=15\ m[/tex]
One of the parallel sides is [tex]20\ m[/tex]
Suppose the other parallel side is [tex]x[/tex]
The area of the trapezium is
[tex]A=\dfrac{1}{2}\times [\text{Sum of parallel sides}]\times h[/tex]
Put values
[tex]\Rightarrow 480=\dfrac{1}{2}\times [20+x]\times 15\\\\\Rightarrow 480\times 2=300+15x\\\Rightarrow 960-300=15x\\\Rightarrow x=44\ m[/tex]