Question

Find 'x' for each trapezium.

Answer 1

Answer:

(i) $area \: of \: trapezium \: = \frac{a + b}{2} \times h \\ \\ area = 70 {cm}^{2} \\ \\ a = 11 \: cm \\ \\ b = 17 \: cm \\ \\ 70 = \frac{11 + 17}{2} \times x \\ \\ 140 = 28 \times x \\ \\ \frac{140}{28} = x \\ \\ 5 cm \: =x$

(ii) $a = 6cm \\ \\ b = 10cm \\ \\ area \: = 68 {cm}^{2} \\ \\ 68 = \frac{10 + 6}{2} \times x \\ \\ 68 = \frac{16}{2} \times x \\ \\ \frac{68}{8} = x \\ \\ 8.5 cm \: = x$

(iii) $a = 12.4 \\ \\ b = 7.6 \\ \\ area \: = 115 {cm}^{2} \\ \\ 115 = \frac{12.4 + 7.6}{2} \times x \\ \\ 115 = \frac{20}{2} \times x \\ \\ 115 = 10 \times x \\ \\ 11.5cm = x$