Student Tutorial: Geometry Basics: Classifying Triangles by Angle

Instructions:

Learn about types of triangles. For this tutorial you'll be using the Desmos Geometry Tools, which are free: https://www.desmos.com/geometry. Watch the video and follow along using the Desmos tools.

Click the arrows on the bottom to get started

Math Clip Art: Student Tutorial Title Page

Acute Triangle. A triangle whose three interior angles are not greater than 90° in measure.

Right Triangle. A triangle with one right angle and two acute angles. The relationship among the sides is summarized by the Pythagorean Theorem.

Obtuse Triangle. A triangle, one of whose interior angles is greater than 90° in measure.

Isosceles Triangle. A triangle with two congruent sides and congruent base angles.

Equilateral Triangle. A triangle with three congruent sides and three congruent interior angles.

Classifying Triangles by Angle Title Card

A triangle includes three angles whose sum is 180°.

An Acute Triangle consists of three acute angles.

A right Triangle consists of one 90° angle and two acute angles.

An Obtuse Triangle consists of one obtuse angle and two acute angles.

An Isosceles Triangle has two congruent acute angles.

An Equiangular Triangle consists of three acute angles of 60°

Triangles Classified by Angles

Examples of acute triangles. The Yield sign is equiangular and the other sign is isosceles.

Right triangle portion of a truss.

Obtuse triangle in the structure of the roof.

Equilateral triangle portion of a truss.