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.
In ΔBAC and ΔADC, ∠BAC=∠ADC=90o (AD ⊥ BC)
∠ACB = ∠DCA (common)
So, Δ BAC ~ ΔADC
ar(ΔABC)ar(ΔADC)=ar(ΔBAC)ar(ΔADC)=BC2AC2
=13252=16925
Therefore, the ratio of the areas of ΔABC and ΔADC = 169 : 25