Question

10
D
Fig. 1.71
A
2. In A ABC, B - D-C and BD = 7,
BC = 20 then find following ratios.
(1)
A(A ABD)
A(A ADC)
A(A ABD)
(2)
A(A ABC)
B
A(A ADC)
(3)
A(A ABC)
C С
D
Fig. 1.72
at​

Answer 1

Answer:

Draw AE ⊥ BC, B – E – C. BC = BD + DC [B – D – C] ∴ 20 = 7 + DC ∴ DC = 20 – 7 = 13 i. ∆ABD and ∆ADC have same height AE. A(ΔABD)/A(ΔADC) = BD/DC [Triangles having equal height] ∴ A(ΔABD)/A(ΔADC) = 7/13 ii. ∆ABD and ∆ABC have same height AE. A(∆ABD)/A(∆ABC) = 7/20 [Triangles having equal height] ∴ A(ΔABD)/A(ΔABC) = 7/20 iii. ∆ADC and ∆ABC have same height AE. A(ΔADC)/A(ΔABC) = DC/BC [Triangles having equal height] ∴ A(ΔADC)/A(ΔABC) = 13/20.