Question

Find the measurement of
an interior angle of a regular
decagon (10-sided figure).

Answer 1

144°

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

1. Brackets
2. Parenthesis
3. Exponents
4. Multiplication
5. Division
6. Addition
7. Subtraction

• Left to Right

Geometry

• Sum of Angles: 180(n - 2)

Explanation:

Step 1: Define

Number of sides n = 10

Step 2: Find

1. Substitute: 180(10 - 2)
2. Subtract: 180(8)
3. Multiply: 1440°

Step 3: Find 1 angle

We have 10 sides.

1. Divide: 1440/10 = 144