Triangle Inequality Theorem
Grade 10th Grade · Math · 45 min
What's Included
Learning Objective
I can determine if three side lengths form a triangle using the triangle inequality theorem.
Warm-Up Video
Destress Math · 7:14
Triangle Basics - Triangle Existence and Triangle Inequality Theorem
Guided Notes
3 key concepts
- 1
The triangle inequality theorem states that the sum of the two smaller sides of a triangle must be greater than the longest side.
- 2
To find the possible range for the third side of a triangle, you must subtract the two given sides to find the lower bound and add them to find the upper bound.
- 3
If given two sides of a triangle of lengths 7 and 5, the third side (x) must fall in the range 2 < x < 12.
Practice Questions
9 questions · Multiple choice & Short answer
Exit Ticket
Quick comprehension check
“The lengths of two sides of a triangle are 8 cm and 10 cm. What is a possible length for the third side? Explain your answer.”
Complete Lesson Package
Get all 3 ready-to-use resources:
