Question

If the length of the parallel sides of an isosceles trapezium are 20 cm and 30 cm and its area is 100 cm2, then the length of non-parallel side is

Answer 1

draw a figure like that in the above figure
To find-- AD and BC
here we have
area trapezium(ABCD)= 100
1/2×h×(AB+DC) =100
1/2×h×(20+30)=100
1/2×h×50=100
50h=200
h=4 cm
thus, in triangle AED
by Pythagoras theorem
AE^2+ED^2 = AD^2
(4)^2 + (5)^2 = AD^2
16+25= AD^2
√41=AD
or, AD= √41 cm
similarly, by using Pythagoras theorem in triangle BFC we get
BC= √41 cm
Thus, the length of non parallel sides of the triangle, that is AD and BC is, √41 cm