Question

The area of triangle ABC is 20. The area of triangle BDC is:
(Picture will be shown below)

Answer 1

After doing a little equation, I know that the height is 8. So,

Answer 2

.5*(AB)*(H)=20 Implies H=40/(AB)
let AB=x
in triangle BDC area is .5*(BD)*H but BD=AB/5
area=.5(AB)/5*H
=AB*H/10 but AB*H=40
therefore area of BDC is 40/10=4 sq.units

Answer 3

Thanks! You got the correct answer, but the way you wrote the numbers and letters takes me a longer time to compute. But I'll eventually understand it in the next few minute or so.