Question

What is the perimeter of △ABC?

Round each step to the nearest tenth.

https://static.k12.com/nextgen_media/assets/1583036-IM1_150303_6_Q006Q.jpg

Answer 1

Use the distance formula!! Yay

Answer 2

which is?

Answer 3

http://2.bp.blogspot.com/-GMrbM3fg4NU/VHljne7DleI/AAAAAAAABec/3emecyWG4ew/s1600/Slide1.jpg

Answer 4

@steve816 what numbers do I put into the equation?

Answer 5

so would I put the points into the equation formula?

Answer 6

i think it's 7.2 @steve816

Answer 7

@3mar

Answer 8

am i right? is is 7.2

Answer 9

So Sorry, I was not here!

So if you just plug in a pair of two points in the formula, you will get the distance between them, and we have three sides, so we should this step trible to get the three lengths...

for the first side (-1,4) and (4,-1)
\[distance=\sqrt{(-1-4)^2+(4-(-1))^2}=\sqrt{5^2+5^2}=\sqrt{50}=5\sqrt{2}\]


for the second side (4,-1) and (0,-3)
\[distance=\sqrt{(4-0)^2+(-1-(-3))^2}=\sqrt{4^2+2^2}=\sqrt{20}=2\sqrt{5}\]


for the second side (0,-3) and (-1,4)
\[distance=\sqrt{(0-(-1))^2+(-3-4)^2}=\sqrt{1^2+7^2}=\sqrt{50}=5\sqrt{2}\]


until now, we did not round any steps, so we will get the most accurate result.

Add these leghts up, you will get the perimeter
\[perimeter=5\sqrt{2}+2\sqrt{5}+5\sqrt{2}=18.614=18.6unit\]


I hope that helps!

and
Sorry for being late!