The problem asks to find the complement of an 18° angle.

In geometry, two angles are complementary if their sum equals 90°. Therefore, the complement of any angle can be found by subtracting the angle from 90°.

The calculation is:

$\text{Complement of } 18^\circ = 90^\circ - 18^\circ = 72^\circ$

So, the measure of the complement of an 18° angle is 72°.

Would you like more details or have any questions?

Here are 5 related questions:

1. What is the definition of supplementary angles?
2. How do you calculate the complement of a decimal angle?
3. Can two obtuse angles be complementary?
4. What are examples of real-life situations where complementary angles are used?
5. How do complementary angles apply to right triangles?

Tip: Remember, complementary angles always add up to 90°, while supplementary angles sum to 180°.