Q5 of 805 Page 1

In Fig. 1, DE ll BC, AD = 1 cm and BD = 2 cm. What is the rati0 of the ar(∆ ABC) to the ar(∆ ADE)?


In ∆ ADE and ∆ ABC

∠ ADE = ∠ ABC (alternate angles)


∠ DAE = ∠ BAC (same angle)


By AA theorem


∆ ADE ≈ ∆ ABC


We know that if two triangle are similar then the ratio of


their areas is equal to square of alternating sides.


Ratio of the ar(∆ ABC) to the ar(∆ ADE)




Ratio of the ar(∆ ABC) to the ar(∆ ADE) = 9 : 1


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