Answer:
AB = AD = 22 units
Explanation:
1- solving for r:
We are given that:
AD is congruent to AB
This means that:
AD = AB
2r + 8 = 5r - 13
5r - 2r = 8 + 13
3r = 21
r = 21/3
r = 7
2- getting the value of AB:
Since we calculated the value of r, we can simply substitute in the equation to get AB as follows:
AB = AD = 5(7)-13 = 2(7)+8 = 22 units
Hope this helps :)