Triangles are one of the most fundamental geometric shapes and have a variety of often studied properties including:
Rule 1: Interior Angles sum up to $$ 180^0 $$
Rule 2: Sides of Triangle -- Triangle Inequality Theorem : This theorem states that the sum of the lengths of any 2 sides of a triangle must be greater than the third side. )
Rule 3: Relationship between measurement of the sides and angles in a triangle: The largest interior angle and side are opposite each other. The same rule applies to the smallest sized angle and side, and the middle sized angle and side.
Rule 4 Remote Extior Angles-- This Theorem states that the measure of a an exterior angle $$ \angle A$$ equals the sum of the remote interior angles' measurements. more)
Do all triangles add up to 180?
What are the 3 angles of a triangle?
Name of Triangle | Description |
Acute Triangle | A triangle with 3 acute angles (3 angles measuring between 0° and 90°). |
Obtuse Triangle | A triangle with 1 obtuse angle (1 angle measuring between 90° and 180°). |