Math Problem Statement

A regular polygon has n sides. Each interior angle of the regular polygon is 2x°. Each exterior angle of the regular polygon is (x - 54) / 2°. Find the value of n.

Solution

We are given the following problem involving a regular polygon:

  1. The polygon has nn sides.
  2. Each interior angle is 2x2x^\circ.
  3. Each exterior angle is (x542)\left(\frac{x - 54}{2}\right)^\circ.

Step 1: Relationship between interior and exterior angles

For any polygon, the interior and exterior angles are supplementary, meaning: Interior angle+Exterior angle=180\text{Interior angle} + \text{Exterior angle} = 180^\circ Substituting the given expressions: 2x+(x542)=1802x + \left(\frac{x - 54}{2}\right) = 180

Step 2: Solve for xx

First, clear the fraction by multiplying the entire equation by 2: 2(2x)+(x54)=3602(2x) + \left(x - 54\right) = 360 Simplifying: 4x+x54=3604x + x - 54 = 360 5x54=3605x - 54 = 360 Now, solve for xx: 5x=360+54=4145x = 360 + 54 = 414 x=4145=82.8x = \frac{414}{5} = 82.8^\circ

Step 3: Find the exterior angle

Using the value of x=82.8x = 82.8^\circ, substitute it into the expression for the exterior angle: Exterior angle=82.8542=28.82=14.4\text{Exterior angle} = \frac{82.8 - 54}{2} = \frac{28.8}{2} = 14.4^\circ

Step 4: Use the exterior angle to find nn

For any regular polygon, the sum of the exterior angles is always 360360^\circ, and each exterior angle is 360n\frac{360^\circ}{n}. Therefore, we have: 360n=14.4\frac{360}{n} = 14.4 Solving for nn: n=36014.4=25n = \frac{360}{14.4} = 25

Thus, the polygon has 25 sides.

Would you like any further clarifications on this problem? Here are some related questions you could explore:

  1. How do the interior and exterior angles of a regular polygon relate?
  2. What is the formula for calculating the sum of the interior angles of a polygon?
  3. How would the angles change if the number of sides increased?
  4. What happens to the interior angle as the number of sides approaches infinity?
  5. Can the exterior angle ever be greater than the interior angle?

Tip: Remember, the exterior angle formula 360n\frac{360^\circ}{n} always holds for regular polygons, regardless of their size.

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Math Problem Analysis

Mathematical Concepts

Polygon Angles
Interior and Exterior Angles
Algebraic Manipulation

Formulas

Sum of interior and exterior angles: Interior angle + Exterior angle = 180°
Exterior angle formula for a regular polygon: Exterior angle = 360 / n

Theorems

The sum of the interior and exterior angles of any polygon is supplementary (180°).
The sum of the exterior angles of a polygon is always 360°.

Suitable Grade Level

Grades 9-11