In `DeltaABC,B-D-C` and `BD=7, BC=20`, then find followig ratios:

`(A(DeltaABD))/(A(DeltaADC))`
`(A(DeltaABD))/(A(DeltaABC))`
`(A(DeltaADC))/(A(DeltaABC))`

Explanation

`BD=7,BC=20`
`BD+DC=BC..(B-D-C)`
`:.7+DC=20`
`:.DC=20-7`
`:.DC=13`
`DeltaABD,DeltaADC` and `DeltaABC` have a comon vertex A and their bases BD,DC and BC lie on the same line BC.
`:.` they have equal heights.
Area of triangles with equal heights are proportional to their corresponding bases.
`(A(DeltaABD))/(A(DeltaADC))=(BD)/(DC)`
`:.(A(DeltaABD))/(A(DeltaADC))=7/13`
`(A(DeltABD))/(A(Delta ABC))=(BD)/(BC)`
`:.(A(DeltaABD))/(A(DeltaABC))=7/20`
`(A(DeltaADC))/(A(DeltaABC))=(DC)/(BC)`
`:.(A(DeltaADC))/(A(DeltaABC))=13/20`
`(A(DeltaABD))/(A(DeltaADC))=7/13, (A(DeltaABD))/(A(DeltaABC))=7/20, (A(DeltaADC))/(A(DeltaABC))=13/20`