If A=(10,4) and B=(2,19), what is the length of AB

Question

I dont really understand the concept

Answer 1

Alright, Adrian, this is based on the Pythagorean theorem. Remember that?

 

a² + b² = c²

 

Why? Draw your two points. We can draw a vertical line down from B at 19 to 4 and a horizontal line from there to A. Hey, we have a triangle with AB as the hypotenuse!

 

How long is the vertical line? 19 - 4 = 15. The horizontal line is 10 - 2 = 8.

 

Let's plug in! 15² + 8² = c²

 

225 + 64 = c²

289 = c²

c = √289 = 17

 

Boom.

Answer 2

L = sqrt[(x1 - x2)^2 + (y1 - y2)^2] = sqrt[(10 - 2)^2 + (4 - 19)^2] = sqrt(8^2 + 15^2) = sqrt(64 + 225) = 17