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Mathematics

Geometry Fundamentals

1 lessons

1
Angles and Triangle Properties
48 min

Geometry Fundamentals

Lesson 1 of 1

Angles and Triangle Properties

Master the fundamental properties of angles and triangles through interactive exploration and proofs.

Core48 min

watch: Watch: Angle and Triangle Basics read: Read: Triangle Properties Guide practice: Interactive: Angle Explorer quiz: Practice: Triangle Challenge

Angles and Triangles

Angle Relationships

Complementary: sum to 90Â°
Supplementary: sum to 180Â°
Vertical angles: opposite angles are equal

1

Watch: Angle and Triangle Basics

13 min · watch

Learn to classify angles and understand their relationships.

2

Read: Triangle Properties Guide

12 min · read

Triangle Classification

By Angles

Acute: all angles < 90Â°
Right: one 90Â° angle
Obtuse: one angle > 90Â°

By Sides

Equilateral: all sides equal
Isosceles: two sides equal
Scalene: no sides equal

3

Interactive: Angle Explorer

18 min · practice

Use interactive tools to measure and construct angles.

4

Practice: Triangle Challenge

5 min · quiz

Question

Two angles of a triangle measure 45Â° and 65Â°. What is the third angle?