Answer:
AB is 15
Step-by-step explanation:
AB and BC are equal because the line that goes through the triangle is going through at a 90 degree angle, u can see that by the small square, and u know it's in the middle bc of the short lines on AD and DC, the short lines means that they are congruent, so:
5x = 4x + 3
subtract 4x from both sides
x = 3
Now u have x, put it in the equation
5x = 5(3) = 15
