Question

The area of a trapezium of height $3cm$ is $12c{m}^2$ . If one of the parallel side is $3cm$, then find the other side.

Answer 1

Find the second parallel side

We know that the area of the trapezium can be given as: $A=\frac{1}{2}\times h(a+b)$

Where $h$is the height of the trapezium and $a,b$ are the parallel sides.

Here it is given that,

$$\begin{gathered} A=12c{m}^2 \\ h=3cm \\ a=3cm \end{gathered}$$

Now,

$$\begin{gathered} 12=\frac{1}{2}\times 3(3+b) \\ \Rightarrow 24=3(3+b) \\ \Rightarrow 8=3+b \\ \Rightarrow b=5cm \end{gathered}$$

Hence, the other parallel side is $5cm$.