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Math Handout Lesson 7

 
 
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Math Handout Lesson 7
by Joy Sun - Tuesday, 17 April 2018, 10:10 PM
 

How do I find the perimeter of a triangle when I am given three vertices of a triangle? 

D(5,0) E(-1,6) F(1,-3)

 
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Re: Math Handout Lesson 7
by David Reynoso - Wednesday, 18 April 2018, 9:44 AM
 

You can find the perimeter of a triangle if you know the length of its sides, so you'd just add the length of the three of them. You can use the three points to find the length of its sides by using the distance formula $$d = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}.$$ For example, the distance of the side between the vertices $D$ and $E$ is $$d = \sqrt{(5-(-1))^2 + (0-6)^2}= \sqrt{36 + 36} = \sqrt{72} \approx 8.5 $$