00:01
Given this equiangular triangle, we wish to prove that each of the angles is equal to 60 degrees.
00:07
Now, there are two ways we can do this.
00:10
First of all, we want to observe that each of these angles is equal, which is something we are given.
00:19
So we know all these angles are equal to each other, which means they all have the same measure.
00:26
So for now, let's just call that measure x degrees.
00:31
So each angle is x degrees.
00:36
Now, we know that if we add all these angles together, so angle a plus angle b, plus measure of angle c, we find since they are the three interior angles of a triangle, that they must equal 180 degrees.
00:54
So then we will replace each of these measures with its value of x degrees, so we get x plus x plus x equals 180.
01:08
In other words, 3x equals 180.
01:14
We will now divide both sides by 3 to find that x equals 60.
01:22
So each of these angles has a measure of 60 degrees...