Thread: I'm not understanding this problem I was given (pythagorean theorem, high school)

Hi,
I was given a problem where I have to match expressions in one column with their appropriate expression in another column. I was given:

A (-3,-2), B (7, -2), and C (-1, 5)

Column 1


1. square root of (-3-4)^2 + (0+8)^2

2. |-2 -2|

3. square root of (-3+1)^2 + (-2-5)^2
4. |-5 -5|

5. square root of (7+3)^2 + (-2+2)^2

Column 2


a) Line AC

b) Line BC

c) Line BC

I was able to find the answer for a) and b), but c has me confused. I missed the class on Friday where my teacher probably explained absolute values, but from what I read it seems like the answer might be |-5-5| since |-10| = 10 and the length of line segment BC is close to that, but it's really 10.63 so I'm not sure if that's just a coincidence. Could anyone explain what the answer is for c)?



Thanks!

Hey KevinShaughnessy.

A line embedded in two dimensions has the form y = mx + c. Your wording is a little confusing and I'm not sure what you are getting at.

The question has not been written correctly. In its present form it does not make sense for Line AC or BC etc cannot be measured. we can measure a line segment but not a line. Pl recheck the question.

Whoops! Sorry guys. It probably is line segment as in the second column, AC, BC, and BA (made a typo there in my original post) have a line over them so I think I got the terminology confused. Anyway, you're supposed to take the coordinates provided at the top (A (-3,-2), B (7, -2), and C (-1, 5)) and match them to the appropriate line segment. So AC would be the square root of ((-3+1)^2+((-2)-5) or number 4 in column A. BA would be the square root of (7+3)^2+((-2)-2)^2. BC though doesn't have a corresponding square root equation so it must be one of the absolute value equations. Using the pythagorean theroem you get 10.62, which is kind of close to |-5-5| so could that be it? I hope that makes things clearer.