7-4: Triangle Inequality Theorem. Theorem 7-9 (Triangle Inequality Theorem): The sum of the measures...
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Transcript of 7-4: Triangle Inequality Theorem. Theorem 7-9 (Triangle Inequality Theorem): The sum of the measures...
7-4: Triangle Inequality Theorem
7-4: Triangle Inequality Theorem
Theorem 7-9 (Triangle Inequality Theorem): The sum of the measures of any two sides of a triangle is greater than the measure of the third side.
We use the Triangle Inequality Theorem to determine if three sides can form a triangle.
7-4: Triangle Inequality Theorem
Determine if the three numbers can be measures of the sides of a triangle. 5, 7, 4
5 + 7 > 4 true 5 + 4 > 7 true 7 + 4 > 5 true Since all cases are true, these measures can form a triangle.
11, 3, 7 11 + 3 > 7 true 11 + 7 > 3 true 3 + 7 > 11 false Since there is at least one false statement, these measures
cannot form a triangle.
7-4: Triangle Inequality Theorem
YOUR TURN Determine if 16, 10, and 5 can be the measures of the
sides of a triangle. If not, explain. No, 5 + 10 is not greater than 16
7-4: Triangle Inequality Theorem
If you are given two sides to a triangle, then the unknown side must be: Less than the sum of the known sides, and Greater than the difference of the known sides
Example If two sides of a triangle are 17 and 8, find the range of
possible measures for the third side. 17 + 8 = 25 17 – 8 = 9 The third side must be 9 < x < 25
7-4: Triangle Inequality Theorem
YOUR TURN If two sides of a triangle are 9 and 13, find the range of
possible measures for the third side. 4 < x < 22
7-4: Triangle Inequality Theorem
Assignment Worksheet #7-4
Tomorrow Quiz on 7-1 through 7-3
Monday Distribution of chapter 7 preview
Wednesday Chapter 7 test