- Two angles that are complements of each other add to equal 90 degrees (they are complementary angles).
- One angle measures x degrees.
- The other angle measures 25 more than 4 times the angle that measures x degrees; it measures 4x + 25 degrees.
To find x, set the sum of these expressions (x and 4x + 25) equal to 90 and solve algebraically for x.
90 = x + (4x + 25)
90 = x + 4x + 25
90 = 5x + 25
65 = 5x
13 = x
If you wanted to find the measure of angle x, you'd substitute 13 for x in its expression, 4x + 25.
4x + 25
4(13) + 25
52 + 25
77
Answer:
x = 13
m∠x = 77°