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Psychguy98

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On the coordinate grid, what is the length of segment AB if the coordinates at point A are (7,9) and the coordinates at point B are (13,17)?


can i form a 3-4-5 rt?
 
Psychguy98 said:
On the coordinate grid, what is the length of segment AB if the coordinates at point A are (7,9) and the coordinates at point B are (13,17)?


can i form a 3-4-5 rt?
Click to expand...

Yes you can.
 
Psychguy98 said:
On the coordinate grid, what is the length of segment AB if the coordinates at point A are (7,9) and the coordinates at point B are (13,17)?


can i form a 3-4-5 rt?
Click to expand...

I think you are expected to use the "distance formula" for this problem. This formula can readily be found on the Internet, and should also be in your textbook. (Here's just ONE site: http://www.purplemath.com/modules/distform.htm )

Because this formula applies to finding the distance between ANY TWO POINTS whose coordinates are known, regardless of whether they can be part of a 3-4-5 triangle, it is widely used and the time you spend learning the formula and how to use it will be time well-spent.

Please look up the distance formula, and then try to apply it to your problem. If you're still having trouble, please re-post. Show us the formula, and your attempt to apply it, so that we might see where your difficulty lies.
 
using the formula d = sq. root (x^2 -x^1) + sq. root (y^2 - y^1) , i get sq. root 136 = 11.66?
 
Psychguy98 said:
using the formula d = sq. root (x^2 -x^1) + sq. root (y^2 - y^1) No!

\(\displaystyle d^2 \ = \ (x_2 \ - \ x_1)^2 \ + \ (y_2 \ - \ y_1)^2\)

, i get sq. root 136 = 11.66?
Click to expand...
 
Psychguy98 said:
using the formula d = sq. root (x^2 -x^1) + sq. root (y^2 - y^1) , i get sq. root 136 = 11.66?
Click to expand...


You don't have the formula correct....


d = sqrt[ (x[sub:ldqxw4fo]2[/sub:ldqxw4fo] - x[sub:ldqxw4fo]1[/sub:ldqxw4fo])[sup:ldqxw4fo]2[/sup:ldqxw4fo] + (y[sub:ldqxw4fo]2[/sub:ldqxw4fo] - y[sub:ldqxw4fo]1[/sub:ldqxw4fo])[sup:ldqxw4fo]2[/sup:ldqxw4fo]]

Now, the two given points are (7, 9) and (13, 17). Substitute for x[sub:ldqxw4fo]1[/sub:ldqxw4fo], y[sub:ldqxw4fo]1[/sub:ldqxw4fo], x[sub:ldqxw4fo]2[/sub:ldqxw4fo] and y[sub:ldqxw4fo]2[/sub:ldqxw4fo]:

d = sqrt [ (13 - 7)[sup:ldqxw4fo]2[/sup:ldqxw4fo] + (17 - 9)[sup:ldqxw4fo]2[/sup:ldqxw4fo]]

d = sqrt[ (6)[sup:ldqxw4fo]2[/sup:ldqxw4fo] + (8)[sup:ldqxw4fo]2[/sup:ldqxw4fo]]
d = sqrt(36 + 64)
d = sqrt(100)
d = 10
 
Psychguy98 said:
so 10 is AB? Would I always use this midpoint formula? Thanks.
Click to expand...

I'm sorry...I don't see the "midpoint formula" in this problem at all.

I was HOPING you'd understand that there IS a formula for finding the distance between ANY two points in the coordinate plane if you know the coordinates of those points in the form (x[sub:2tc1t8on]1[/sub:2tc1t8on], y[sub:2tc1t8on]1[/sub:2tc1t8on]) and (x[sub:2tc1t8on]2[/sub:2tc1t8on], y[sub:2tc1t8on]2[/sub:2tc1t8on])

This "distance formula" works every time, regardless of where the points ARE in the coordinate plane.

If you'd let us know what you understand the "midpoint formula" to be, and tell us how you'd apply it to this problem, we (or I, at least) might be better equipped to comment on whether your reasoning is correct.
 
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