Question

the parallel sides of an isosceles trapezium are in the ratio 2 : 3. if its height is 4cm and area is 60 cm2, find the perimeter

Answer 1

let proportionality constant =x
so, length of one side of trapezium=2x and other is 3x
now,
area of trapezium=1/2(2x+3x) x 4
60 cm^2 =10x cm^2
x=6
now length of parallel sides are =12
and 18 cm
length of unparallel sides are equal
which are ---
length= √{(3)^2+(4)^2}=5 cm
now ,
perimeter of trapezium=2(5)+12+18
=40cm

Answer 2

Hi friend,

Let the side be x
Then one parallel side is 2x
Another parallel side be 3x
Height=4cm
Area=60cm^2
Let's find the side......

60=1/2(sum of the parallel sides)×h
60=1/2(2x+3x)4
60×2=2x+3x×4
120=5x×4
120/5=x×4
24=4x
x=24/4
x=6cm

Then one parallel side is 2×6=12
Then other parallel side be 3×6=18

Now the perimeter will be,
Sum of all the sides
12+18+4
=34cm


Hope my answer helped you..............