Question

BC=8cm
DE=6cm
ar(∆ADE) = 45cm^2
Find ar(∆ABC) ?​

Answer 1

where is the length of AB and AC .....???

the length of AB and AC is given in your book and you can solve it by this method which is below....

first we find the area of DECB which is a

trapezium

area of trapezium = 1/2 x sum of parallel sides x height

now we have not height so first we find the height...

BC-DE=BF

8-6=2cm

therefore, BF=2cm

now BF=FC

1/2FC=FG

FC-FG=GC

2-1=1cm

therefore GC=1cm

now, we find height by Pythagoras theorem... it means CGE is a right triangle...

and EG is height..

(EC)^2=(EG) ^2+(GC) ^2

now height is come

and use the formula

area of trapezium = 1/2 x sum of parallel sides x height

= 1/2 x 8+6 x height

and in final step add the area of triangle and area of trapezium

area of trapezium + area of triangle = area of triangle ABC......

hope it help you....

if you satisfy so plss mark it as brainliest.......