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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 \(180°\).