Classify triangles

Learning Objectives Identify the basic components of a triangle (vertices, sides, angles). Classify triangles as equilateral, isosceles, or scalene based on their side lengths. Classify triangles as acute, right, or obtuse based on their angle measures. Determine if a given set of side lengths can form a triangle using the Triangle Inequality Theorem. Apply the sum of angles in a triangle to find missing angle measures. Combine side and angle classifications to fully describe a triangle. Ever notice how many shapes around us are made of three straight lines? 📐 From roof trusses to pizza slices, triangles are everywhere! In this lesson, you'll learn how to sort and name triangles based on their side lengths and angle measures. Understanding these classifications will h...

TermDefinitionExample TriangleA polygon with three straight sides and three interior angles.A slice of pizza is often a triangle. VertexA point where two sides of a polygon meet (plural: vertices).The corner of a triangle where two sides connect. SideA line segment that forms part of the boundary of a polygon.One of the three straight lines that make up a triangle. AngleThe space (measured in degrees) between two intersecting lines or surfaces at or close to the point where they meet.The opening between two sides of a triangle at a vertex. Acute AngleAn angle measuring less than 90 degrees.An angle of 45 degrees. Right AngleAn angle measuring exactly 90 degrees, often marked with a small square symbol.The corner of a square or a perfect 'L' shape. Obtuse AngleAn angle measuring...

Sum of Angles in a Triangle $\\angle A + \\angle B + \\angle C = 180^\\circ$ The sum of the interior angles of any triangle is always 180 degrees. Use this rule to find a missing angle if you know the other two, or to confirm if a set of three angles can form a triangle. Triangle Inequality Theorem $a + b > c$, $a + c > b$, and $b + c > a$ The sum of the lengths of any two sides of a triangle must be greater than the length of the third side. This rule helps determine if three given side lengths can actually form a triangle. If any one of these conditions is not met, a triangle cannot be formed. Equilateral Triangle Property $a=b=c$ and $\\angle A = \\angle B = \\angle C = 60^\\circ$ If a triangle has three equal sides, it must also have three equal angles (...