Question

the parallel sides of trapezium is 77 meter and 60 meter and its non parallel sides are 26 meter and 25 meter. find the area of trapezium

Answer 1

AB=60 m;DF=77 m;AD=25m; BF=26mwe calculate the CF:
CF=DF-CD=77-60=17 m

For ΔBCF,
we calculate the perimeter of triangle
P=BC+BF+CF=25+26+17=68 m
we calculate the  semiperimeter of the triangle:
p=P/2=68/2=34 m
we use the formula of Heron:
At=√p×(p-BC)×(p-BF)×(p-CF);
=√34(34-25)(34-26)(34-17)
=√34×9×8×17=√41616= 204 m²
we calculate the height of triangle:
BE=2At:CF=(2×204):17=408:17=24 m

we calculate the area of Trapezium
A =[(AB+DF)×BE):2=[(60+77)×24]=(137×24):2=3288:2=1644 m²

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