Question

What is the value of x?

A.) -9
B.) -10
C.) 10
D.) -12​

Answer 1

A.) -9

Explanation:

it is observed that triangles ABL and KML are similar triangles

hence the following ratios are valid:

LA / LK = LB/LM = AB/KM

we can see that LA/LK = LB/LM = 1/2

hence the above ratio becomes

1/2 = AB/KM (rearranging)

KM = 2AB

We are given that KM = (x + 21) and AB = (x + 15)

hence

KM = 2AB

(x + 21) = 2 (x + 15)

x + 21 = 2x + 30

x - 2x = 30 - 21

-x = 9

x = -9