Question:
Find the sum of the lengths of the bases of a trapezium whose area is 4.2 m2 and whose height is 280 cm.
Solution:
Given:
Area of the trapezium $=4.2 \mathrm{~m}^{2}$
Height $=280 \mathrm{~cm}=\frac{280}{100} \mathrm{~m}=2.8 \mathrm{~m}$
Area of trapezium $=\frac{1}{2} \times($ Sum of the parallel bases $) \times($ Height $)$
$4.2=\frac{1}{2} \times($ Sum of the parallel bases $) \times 2.8$
$4.2 \times 2=$ (Sum of the parallel bases) $\times 2.8$
Sum of the parallel bases $=\frac{8.4}{2.8}=3 \mathrm{~m}$