Problem:
One angle is equal to three times its supplement. The measure of the angle is?

Solution:
To solve this problem, we need to understand the relationship between an angle and its supplement.

Angle and Its Supplement:
- An angle and its supplement are two angles that add up to 180 degrees.
- Let's assume the angle is 'x' degrees.
- The supplement of the angle is then (180 - x) degrees.

Given Information:
- One angle is equal to three times its supplement.
- Mathematically, this can be represented as: x = 3(180 - x).

Solving the Equation:
To find the measure of the angle, we need to solve the equation x = 3(180 - x).

Step 1: Distribute the 3 to the terms inside the parentheses.
x = 540 - 3x

Step 2: Add 3x to both sides of the equation to isolate the variable.
x + 3x = 540

Step 3: Combine like terms.
4x = 540

Step 4: Divide both sides of the equation by 4 to solve for x.
x = 135

Answer:
The measure of the angle is 135 degrees.

Explanation:
The given information states that one angle is equal to three times its supplement. By using the fact that the sum of an angle and its supplement is 180 degrees, we can set up an equation. Solving this equation, we find that the angle is 135 degrees.