Answer:
u = 9
Explanation:
angle c and a are congruent so take the 2 angles and turn them into an equation
u + 99 = 12u
subtract 1u from both sides, you're left with 99 = 11u
now, divide each side by 11
now you'll get the value of u which is 9 (u = 9)
since 99/11 is 9 that's the value of u.