D is on side AC of Triangle ABC. We know [ABC] = 120, AD = 8, DC = 3. What is [ABD]?
B
A 8 D 3 C
Note that triangles ABD and DBC are under the same height
And....triangles under the same height are to each other as their bases
So
[ABD ] = [ 8 / ( 8 + 3) ] [ ABC] = (8/11) (120) = 960 / 11
