Someone please help out. How do I solve this?

Answer:
b = 15
Step-by-step explanation:
since line UV and TW are congruent you can take both of numbers on those lines and turn it into an equation.
2b - 15 = b
first, subtract 2b from both sides, you're left with -15 = -b
then, divide each side by -1
-15 divided by -1 turns it into a positive 15 which is b.