anonymous 3 years ago 1. Find the distance between point A(-3, 5) and point B(4, -6) in the coordinate plane.

1. anonymous

$d=\sqrt{(x-x1)^2 + (y-y1)^2}$

2. anonymous

$d = \sqrt{(-3+4)^{2} + (5-6)^{2}}$

3. anonymous

D=$\sqrt{(Y2-Y1)^2+(X2-X1)^2}$

4. Kainui

That's not just some random formula, it's the pythagorean theorem. Start thinking about points on a coordinate plane as really being triangles.

5. anonymous

when we have something to calculate why to waste time

6. anonymous

because if you think, you can just about do it in your head the distance between -3 and 4 is 7 the distance between -6 and 5 is 11 so you have a right triangle, one side is 7, the other sides is 11 and the hypotenuse (distance) is $\sqrt{7^2+11^2}$

7. Kainui

Exactly. Plus, if you understand the concept, you can use that to help you learn new things or solve problems similar, which just knowing the formula can't help you with.

8. anonymous

good point