Geometry

##### Related Lessons

- 3 4 5 Triangle
- 30 60 90 Triangle
- 45 45 90 Triangle
- 5 12 13 Triangle
- Arc Length Calculator
- Area of a Circle Calculator
- Area of a Hexagon
- Area of a Kite
- Area of a Parallelogram
- Area of a Pentagon
- Area of a Rectangle
- Area of a Rhombus
- Area of a Sector
- Area of a Semicircle
- Area of a Square
- Area of a Trapezoid
- Area of a Triangle
- Center of Mass Calculator
- Circumference Calculator
- Distance Formula
- Distance Formula Calculator
- Geometry Calculators
- How to Find the Height of a Triangle
- Isosceles Triangle Theorem
- Perimeter of a Circle
- Perimeter of a Pentagon
- Perimeter of a Rectangle
- Perimeter of a Rhombus
- Perimeter of a Semicircle
- Perimeter of a Square
- Perimeter of a Trapezoid
- Perimeter of a Triangle
- Properties of a Parallelogram
- Pythagorean Theorem Calculator
- Side Angle Side Theorem
- Side Splitter Theorem
- Similar Triangles
- Special Right Triangles
- Surface Area of a Cone
- Surface Area of a Cube
- Surface Area of a Cylinder
- Surface Area of a Hemisphere
- Surface Area of a Pyramid
- Surface Area of a Sphere
- Surface Area of a Triangular Prism
- Triangle Inequality Theorem
- Types of Triangles
- Vertical Angles
- Volume of a Cone
- Volume of a Cube
- Volume of a Hexagonal Prism
- Volume of a Pyramid
- Volume of a Sphere
- Volume of Hemisphere
- Volume of Parallelepiped

Tutors/teachers:

Nikkolas

Tutor and Aerospace Engineer

# Types of Triangles

#### Lesson Contents

## The 6 Main Types of Triangles: by Side and by Angle

Triangles types are named and classified by their sides and by their angles.

By Angle:**Acute Triangle — All angles are less than 90°.****Right Triangle — Has an angle that is exactly 90°.****Obtuse Triangle — Has one angle that is more than 90°.**

By Side:**Equilateral Triangle — All three sides are equal in length.****Isosceles Triangle — Two sides are equal in length.****Scalene Triangle — Has no sides that are equal in length.**

### Special Types of Right Triangles

Within the right triangle, there are 4 special right triangles. The special right triangles by angles are the 45-45-90 Triangle and the 30-60-90 Triangle. The special right triangles by sides are the 3-4-5 Triangle and the 5-12-13 Triangle.

Result :

Worksheet 1

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Cheat sheet

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