I could use some help on this​

A

Step-by-step explanation:

The length of CD represents the distance between the points C and D. Counting the points between them, if we start from point D, we need to get through points 1, 2, and 3 to get to C. That is 3 units, or A

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so: