Δ ABC sim Δ DEF and the area of Δ ABC is 13.5 cm² and the area of Δ DEF is 24 cm². If BC = 3.15 cm, then the length (in cm) of EF is:

Δ ABC sim Δ DEF and the area of Δ ABC is 13.5 cm² and the…

$\Delta$ ABC $\sim$ $\Delta$ DEF and the area of $\Delta$ ABC is 13.5 cm² and the area of $\Delta$ DEF is 24 cm². If BC = 3.15 cm, then the length (in cm) of EF is:

Show answer & explanation

Correct answer: C

Explanation

The correct answer is option 3 i.e. 4.2

The ratio of the area of two similar triangles is directly proportional to the squares of the corresponding sides.

⇒ ar( $\Delta$ ABC) : ar( $\Delta$ DEF) = BC² : EF²

⇒ 13.5/24 = (3.15)²/EF²

⇒ 3/4 = 3.15/EF

⇒ EF = 4.2

SSC CGL 2021 PYQ — Question 68