# The Sum of Exterior Angles in Geometry

Geometry is a branch of mathematics that deals with shapes, sizes, angles, and positions. One concept of geometry involves the sum of exterior angles in a triangle. A triangle is a three-sided shape composed of three straight line segments connecting at the corners to form three interior angles that add up to 180 degrees. The exterior angle is the angle formed when two sides of a triangle are extended outward from the vertex. In this blog post, we’ll discuss why the sum of exterior angles in a triangle is equal to 360 degrees.

## The Definition of an Exterior Angle

An exterior angle is an angle located outside the triangle outside one of its sides and opposite its vertex point. This means that if you extend one side or two sides on either side, it will form an angle with both lines. An exterior angle can be described as being supplementary with respect to its adjacent interior angle; meaning it's equal to 180 minus the measure of its adjacent interior angle. For example, if one interior angle measures 30 degrees, then its supplementary exterior angle would be 150 degrees (180 - 30 = 150). All triangles have three exterior angles, each being supplementary to an interior angle.

## Why Is the Sum Equal To 360?

The sum of all three exterior angles in any triangle equals 360 degrees for a very simple reason—each time you traverse around a point or vertex, you make a full circle which adds up to 360 degrees total! This means that if you connect all three points together or “traverse” around them in any order, it will add up to 360 degrees total when you finish making your circle back at your starting point. So regardless of how many sides there are or what size each side may be, whenever you traverse around these points it will always add up to 360 degrees total!

## Conclusion

In conclusion, understanding the sum of exterior angles in geometry can help students better understand other mathematical concepts like circles and arcs as well as 3D figures like spheres and cylinders. By remembering that each time you traverse around any set of points it will add up to 360 degrees total can help students quickly solve many math problems involving triangles and other shapes with similar properties. It’s also important for students to remember that each external angle formed by extending two sides outwards from their common vertex is supplementary with respect to its adjacent interior angle so they can determine their exact measure without having to calculate it manually every time they come across such problems.

## FAQ

### What is the sum of the exterior angles of a triangle?

The sum of all three exterior angles in any triangle equals 360 degrees.

### What is an exterior angle?

An exterior angle is an angle located outside the triangle outside one of its sides and opposite its vertex point. This means that if you extend one side or two sides on either side, it will form an angle with both lines.

### How do you find the sum of exterior angles?

The sum of the exterior angles can be found by traversing around the points in a circle, which will add up to 360 degrees in total. Additionally, each external angle formed by extending two sides outwards from their common vertex is supplementary with respect to its adjacent interior angle so they can determine their exact measure without having to calculate it manually every time.

### What is the exterior angle theorem in geometry?

The exterior angle theorem states that the measure of an exterior angle of a triangle is equal to the sum of the measures of its two remote interior angles. This means that if you know the measure of one interior angle and its adjacent exterior angle, then you can easily calculate the measure of the other two interior angles in the triangle.