Question

Difficulty: EasyPolygon Angles and Properties

A regular decagon has 1010 sides of equal length. What is the measure, in degrees, of one exterior angle of this decagon?

Answer: 36 degrees

Answer

The correct answer is 36.
The sum of the exterior angles of any convex polygon is always 360360^\circ. A regular decagon has 1010 congruent sides and therefore 1010 congruent exterior angles. Dividing 360360^\circ by 1010 yields 3636^\circ for each exterior angle.

Step-by-Step Solution

1
Determine the number of exterior angles in a regular decagon.
A decagon has 10 sides, so it has 10 exterior angles.
A polygon has the same number of exterior angles as its number of sides.
2
State the sum of the exterior angles for a convex polygon.
The sum of the exterior angles is 360 degrees.
The exterior angles of any convex polygon always sum to 360 degrees regardless of the number of sides.
3
Calculate the measure of one exterior angle.
360 / 10 = 36
Since the decagon is regular, all of its exterior angles are equal in measure, so we divide the total sum by the number of angles.

Key Concept

The sum of the exterior angles of any convex polygon is 360360^\circ. For a regular polygon with nn sides, the measure of each exterior angle is 360n\frac{360^\circ}{n}.
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