### Theory:

Let's see the remarkable property that connects three angles of a triangle.
The sum of the measure of three angles of a triangle is 180°.
Example:
Consider a triangle $$ABC$$ with interior angles measures $$∠1$$, $$∠2$$ and $$∠3$$.

By the sum of measure of angles of triangle property, $$∠1 + ∠2 + ∠3 = 180°$$.
Important!
In a triangle:
• If the measure of all angles are different, then all sides are different.
• If the measure of two angles are equal, then two sides are equal.
• If the measure of three angles are equal, then three sides are equal and each angle measures $$60°$$.
• Sum of three angles of a triangle is $$180°$$.