Answer with Step-by-step explanation:
Since we have given that
Angle 12 and angle 11 are complementary.
Mathematically, it is expressed as
------------(1)
measure of angle 10 + measure of angle 11 = 90 degrees.
Mathematically, it is expressed as
----------------(2)
From eq(1), and eq(2), we get that

Hence, angle 12 is congruent to angle 10.
Answer:
Step-by-step explanation:
<UWV = 180° - 50° - 50° ( SUM OF ANGLE IN A TRIANGLE)
<UWV = 80° which is angle A
b = 20 ( isosceles triangle)