Question

∆ABC ∼ ∆DEF, ar(∆ABC) = 9 cm², ar(∆DEF) = 16 cm². If BC = 2.1 cm, then the measure of EF is 

विकल्प

• 2.8 cm

• 4.2 cm

•  2.5 cm

• 4.1 cm

Answer 1

Given: `Ar(Δ ABC)=9cm^2,AR(Δ DEF)=16 cm^2` and `BC= 2.1 cm`

To find: measure of EF

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

`(Ar(Δ ABC))/(Ar(Δ DEF))=(BC)^2/(EF)^2`

`9/16=(2.1)^2/(EF)^2`

`3/4=2.1/(EF)`

`EF=2.8 cm`

Hence the correct answer is `a`