Interior Angles Of A Triangle
In these lesson, we will learn
- about interior angles of triangles
- the properties of the interior angles of a triangle
- how the properties can be used to find the missing angles inside a triangle
- how the sum of interior angles of a triangle can be used to set up equations.
Related Pages
Exterior Angles Of A Triangle
Types Of Triangles
Angles In A Triangle
The following diagram shows that the sum of angles in a triangle is 180°. Scroll down the page for more examples and solutions on how to find missing angles in a triangle.
Interior Angles
The interior angles of a triangle are the angles inside the triangle.
Properties of Interior Angles
- The sum of the three interior angles in a triangle is always 180°.
- Since the interior angles add up to 180°, every angle must be less than 180°.
Find missing angles inside a triangle
Example:
Find the value of x in the following triangle.
Solution:
x + 24° + 32° = 180° (sum of angles is 180°)
x + 56° = 180°
x = 180° – 56° = 124°
How to find the missing angle inside a triangle.
Example:
Find the missing angle in a triangle.
A = 15°, B = ?, C = 92°
Using Interior Angles Of Triangle To Set Up Equations
How to use the sum of the interior angles of a triangle to solve problems?
Example:
- Write an equation and solve for the unknown.
- Substitute your answer into each expression to determine the measure of the angles.
- Give reasons for your answers.
Using the sum of the interior angles of a triangle, write an equation and solve for the unknown.
Try out our new and fun Fraction Concoction Game.
Add and subtract fractions to make exciting fraction concoctions following a recipe. There are four levels of difficulty: Easy, medium, hard and insane. Practice the basics of fraction addition and subtraction or challenge yourself with the insane level.
We welcome your feedback, comments and questions about this site or page. Please submit your feedback or enquiries via our Feedback page.