Question

solve the question number 2

Answer 1

you can undrstand it if u learn triangles theorem deeply

Answer 2

GIVEN
BD = 7
BC = 20
Therefore, DC = 20 - 7 = 13

DRAW A VERTICAL LINE FROM POINT 'A' POINT E ON BASE BC.
This vertical line is a height or altitude and it is always perpendicular to base. Means form 90 degree.

FORMULA
Area of triangle = 1/2 x (height x base)
CASE 1.
ar ABD / ar ADC
= 1/2 (AE x BD) / 1/2(AE x DC)
= BD / DC
= 7 / 13

CASE 2.
ar ABD / ar ABC
= 1/2 (AE x BD) / 1/2(AE x BC)
= BD / BC
= 7 / 20

CASE 3.
ar ADC / ar ABC
= 1/2 (AE x DC) / 1/2(AE x BD)
= DC / BD
= 13 / 7