Q12 of 32 Page 6

ΔABC is right-angled at A and AD ⊥ BC. If BC = 13 cm and AC = 5 cm, find the ratio of the areas of ΔABC and ΔADC.

(CBSE 2000)

In ΔABC and ΔADC


∴∠ BAC = ∠ ADC (90° angle)


∠ ACB = ∠ ACD (Common)


So, by AA similarity criterion ΔADC ~ ΔABC


We know that if two triangles are similar then the ratio of their areas is equal to the ratio of the squares of their corresponding sides.



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