Option A:
ΔDEF
ΔABC; x = 1.5; CB = 3.9; AB = 3;
![(2)/(3)](https://img.qammunity.org/2021/formulas/mathematics/high-school/54kd5otoayi7fslqp2ejx77tdkhh8ubevy.png)
Solution:
Each pair of given polygons are similar.
Similarity statement for the given polygons:
In ΔDEF and ΔABC,
∠D = ∠A (Angle)
∠E = ∠B (Angle)
Therefore, ΔDEF
ΔABC (by AA similarity)
If two triangles are similar, then their sides are proportional.
![$\Rightarrow (DF)/(AC) =(DE)/(AB)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/m748sg11geup3mj4g8s2v7n85p1ucacvl6.png)
![$\Rightarrow (2.4)/(3.6) =(2)/(2x)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/5k9o3svpvviweelseaqku55j32natmhx4j.png)
Do cross multiplication,
⇒ 2.4 × 2x = 2 × 3.6
⇒ 4.8x = 7.2
⇒ x = 1.5
Substitute x = 1.5 in CB and AB,
CB = 3x – 0.6
= 3(1.5) – 0.6
CB = 3.9
AB = 2x
= 2(1.5)
AB = 3
Scale factor means ratio of the sides of the triangle.
![$\Rightarrow (DF)/(AC) =(2.4)/(3.6)=(2)/(3)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/oggisl4rvupa5p5a84cs1j0ews4lmqnqrn.png)
Therefore, Option A is the correct answer.
Hence ΔDEF
ΔABC; x = 1.5; CB = 3.9; AB = 3;
.