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

Answer 1

Area of a trapezium is 1/2(a+b)h,
where, a and b are the parallel sides,and  
            h is perpendicular height.

So, if we divide the area(4.2*100*100=42000) by height,
we get 1/2 of the sum of a and b.
                   42000/280= 150.

Sum of parallel sides = 150*2=300cm=3m.
1.5m*2.8m=4.2 Sq. Meter.

Answer 2

your ans is in this pic