Question

Find the area of the trapezium ABCD in which AB//DC , AB= 18cm , angle B = angle C = 90° , CD = 12cm and AD = 10cm.

Answer 1

given AB=18,DC=12 and AD=10 and angle B equal to C .
draw a line segment from D to point E at AB
Then DC =BE
BE=12cm.
Then it make the triangle ADE
AD²=DE²+AE²
10²=DE²+6²
DE=√10²-6²
DE=√100-36
DE=√64
DE=8cm
height of trapezium =8cm
area of trapezium=1/2(sum of parallel sides)×height
area=1/2×(12+18)×8
area=30×4
area of trapezium=120cm²

Answer 2

given AB=18,DC=12 and AD=10 and angle B equal to C .

draw a line segment from D to point E at AB

Then DC =BE

BE=12cm.

Then it make the triangle ADE

AD²=DE²+AE²

10²=DE²+6²

DE=√10²-6²

DE=√100-36

DE=√64

DE=8cm

height of trapezium =8cm

area of trapezium=1/2(sum of parallel sides)×height

area=1/2×(12+18)×8

area=30×4

area of trapezium=120cm²