# 360 degrees circle

Im doing a proof. For instance all sums of a triangle add upp to 180 degrees. But how to i motivate that all arcs on a circle add up to 360 degrees.

A part of my proof is that Arc A + B + C = 360 degrees.

But i dont know what to write in the column that motivates every step. ! Like a lap is 360 degrees dosent sound good enough

## Answers and Replies

Merlin3189
Homework Helper
Gold Member
Usually we just say, angles at a point sum to 360o
I think that is a definition of degrees.

Mark44
Mentor
Im doing a proof. For instance all sums of a triangle add upp to 180 degrees. But how to i motivate that all arcs on a circle add up to 360 degrees.

A part of my proof is that Arc A + B + C = 360 degrees.

But i dont know what to write in the column that motivates every step. ! Like a lap is 360 degrees dosent sound good enough
In future posts, please don't delete the homework template. Its use is required.

pasmith
Homework Helper
Usually we just say, angles at a point sum to 360o
I think that is a definition of degrees.

Very much this.

member 587159
Very much this.

This is true. We have chosen to use a 360degree system for a circle but other systems like a 400 degree system (have) exist(ed) as well.