Triangle Inequality Theorem

​Triangle Inequality Theorem

Mr. Rodriguez​

Sides of a triangle

• 3+4>5, 3+5>4, 5+4>3

• The sum of the shorter sides needs to be greater than the larger side.

• 3 + 4 < 9

Not a triangle

• 1 + 2 = 3

• Is not greater than 3

• Cannot form a triangle

Triangle

• 7, 13, 18

• Forms a triangle

• 7 + 13 = 20

• 20 > 18

Multiple Choice

Determine if the 3 numbers can be measures of the sides of a triangle. 9, 8, 10

• Yes

• No

Multiple Choice

Determine if the 3 numbers can be measures of the sides of a triangle. 4, 16, 19

• Yes

• No

Multiple Choice

Determine if the 3 numbers can be measures of the sides of a triangle. 9, 11, 20

• Yes

• No

Multiple Choice

Determine if the 3 numbers can be measures of the sides of a triangle. 9, 15, 26

• Yes

• No

Multiple Choice

Determine if the 3 numbers can be measures of the sides of a triangle. 9, 12, 20

• Yes

• No

Multiple Choice

Determine if the 3 numbers can be measures of the sides of a triangle. 6, 14, 21

• Yes

• No

Multiple Select

Which of the following sets of side lengths could produce a triangle. SELECT ALL THAT APPLY.

• 4, 4, 4

• 5, 5, 10

• 3, 6, 9

• 5, 7, 11

• 13, 5, 6

Given 2 sides of a triangle determine the range of possible lengths for the third side

Add the 2 numbers, Subtract the 2 numbers....the third side must be BETWEEN these 2 numbers (not equal to them!)

Open Ended

Name a possible length for the third side of a triangle with sides 4 and 7.

Open Ended

Name a possible length for the third side of a triangle with sides 11 and 19.

Multiple Select

Which of the following could be the third side of a triangle with sides 5.2 and 7.2? Check all that apply.

• 21

• 2

• 9

• 12.4

• 11

Multiple Select

Which of the following could NOT be the third side of a triangle with sides 35 and 14? Check all that apply.

• 21

• 48

• 26

• 35

• 14

Multiple Choice

If the measures of 2 sides of a triangle are 57 and 32, what is the LEAST possible measure of the third side if the measure is an integer?

• 25

• 26

• 88

• 89

​IXL Assignments

Please work on the following IXL Skills

​

7.W.4

7.W.21​

Some text here about the topic of discussion