Help with finding the distance between two points?

Question

I'm working on a multiple choice and the answers are different than my answers...

Here are the distances:
1. (-4,2) - (4,-2)
2. (-1,3) - (-3,-2)
3. (1,4) - (3,0)
4. (-4,2) - (4,3)

For problem 1. my answer was 4√5 and the only choices are
√86
√89
2√17

I don't know what to do...

Answer 1

1. Subtract the two points
(-4, 2) - (4, -2) = (-8, 4)
Now do the square root thing
sqrt(64 + 16) = sqrt(80) = 4 sqrt(5)
I get the same as you. Make sure you are reading the problem correctly.

Answer 2

Here is the formula for finding distance between 2 points:

d = square root of [ (x2 - x1)^2 + (y2 - y1)^2 ]

from no. 1, d = sq. rt. [(-4 - 4)^2 + (2-(-2))^2 ]
d = sq. rt. (64 + 16)
d = sq. rt. (80)
d = 4 sq. rt. 5

I think the answer is not in the options...

Answer 3

look at # 1

the distance is given by the formula

[(x1-x2)^2 +(y1-y2)^2]^0.5

[(-4-4)^2 + (2--2)^2]^0.5 =
[64 + 16]^0.5 =
80^0.5 = 4 (5)^0.5 which is what you calculate

I suspect the multiple choices are wrong.

Answer 4

let the two points be A(x1,y1) and B(x2,y2).
distance of AB= √[(y2-y1)^2+(x2-x1)^2]

therefore, for qn1, the answer is 4√5 and you're right (:

Answer 5

huh?......