Question

Find the lengths of DE and EF. Note: Segments BC and DF are parallel

Answer 1

the answer is c

Explanation:

you have to create a proportion ( it being 5x-4/3=4x+2/5) then after you cross multiply from that proportion you plug in x. and don't forget to add the other part of the triangle as well.

Answer 2

C

Explanation:

Given that Segments BC and DF are parallel, then the following proportion must be satisfied:

BE/EC = DE/EF

Replacing with data from the picture:

3/5 = (5x - 4 + 3)/(5 + 4x + 2)

3*(7 + 4x) = (5x - 1)*5

21 + 12x = 25x - 5

21 + 5 = 25x - 12x

26 = 13x

x = 2

Then,

DE = 5x - 4 + 3 = 5(2) - 4 + 3 = 9 cm

EF = 5 + 4x + 2 = 5 + 4(2) + 2 = 15 cm