Question

Find the are of a trapezium whose parallel sides are 25 cm, 13 cm and other sides are 15 cm and 15 cm.​

Answer 1

Answer:

57√21cm^2

Step-by-step explanation:

abcd is a trapezium

ab=25

DC=13

ad and bc=15cm

are=DC=13(opp. sides are equal)

be=ab-ae

be=25-13

=12cm

in triangle be

s=a+b+c/2

=15+15+12/2

=21

area of triangle bce=√s[s-a][s-b][s-c]

=√21(21-15)(21-15)(21-12)

=√21x6x6x9

=18√21cm^2

area of bce=1/2(bxh)

=1/2x12xh

=6h

6h=18√21

h=18√21/6

h=3√21

height of trapezium is equal to the height of triangle bce

area of trapezium=1/2(ab+cd)

=1/2(25+13)x3√21

=57√21cm^2