Question

the parallel sides of a trapezium is 120 cm and140 cm and non parallel sides are 50 cm and 52 cm find the area of the trapezium​

Answer 1

In trapezium ABCD

join BD..

Now in ∆ABD and ∆CDB,

sideAB =sideCD

angle ABD = angle CDB

sideBD = sideBD

∆ABC congruent to ∆CDB.... by SAS

ar(∆ABC) =are(∆CDB)..... 1

Now in ∆ABC,

by angle sum property,

AB+BD+AD= 180°

120+BD+50=180°

BD=180-170

BD=10 cm

ar(∆ABC) = 10 cm^2

from 1,

ar(∆ABC) =ar(∆CDB)

ar(∆CDB) =10cm^2

trapezium ABCD= 10+10

=20cm^2