Question

In ΔABC and ΔDEF, we have `(AB)/(DE) = (BC)/(EF) = (AC)/(DF) = 5/7`, then ar(ΔABC) : ar(ΔDEF) = ?

Options

• 5 : 7

• 25 : 49

• 49 : 25

• 125 : 343

Answer 1

25 : 49

Explanation:

The triangles are similar corresponding sides in ratio 5 : 7. 

The ratio of areas of similar triangles equals the square of the ratio of corresponding sides, so `ar(ΔABC) : ar(ΔDEF) = (5/7)^2 = 25 : 49`.