Given that the perimeters of two similar triangles, ∆ABC and ∆DEF, are 24 cm and 9 cm, respectively, and DE = 3 cm, what is the ratio between the area of ∆ABC and that of ∆DEF?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 64 : 9.
Given:
Perimeter of ΔABC = 24 cm
Perimeter of ΔDEF = 9 cm
DE (a side of ΔDEF) = 3 cm
First, we find the ratio of the perimeters:
Ratio of perimeters= = =
Since the triangles are similar, the ratio of their corresponding sides is the same as the ratio of their perimeters:
The ratio of corresponding sides =
The ratio between the area of ∆ABC and that of ∆DEF = = (The ratio of the areas of similar triangles is the square of the ratio of their corresponding sides)