Question

The area of trapezuim is 279 sq cm .The distance between its parallel sides is 18cm and one of the parallel sides is 13 cm .Find the length of the other side.

Answer 1

area= 1/2×h (sum of parallel side)
279=1/2×18 (x+13)
279=9 (x+13)
279/9=x+13
31=x+13
31-13=x
18=x

Answer 2

area = 279 cm²

height = 18cm

one of the parellal side = 13cm

let other side be ' b '


$area \: of \: trapezium \: = \frac{1}{2} h(a \: + b)$
$279 = \frac{1}{2} 18(13 + b)$
$\frac{279 \times 2}{18} = 13 + b$
31 = 13 + b

b = 31 - 13

b = 18

other parellal side = 18cm