Question

Find the distance between the points (-4, 6) and (8, -12).Round your solution to 2 decimal points.

Answer 1

Use pythagoras.

sqrt((6--12)^2 + (8--4)^2) = 6*sqrt(13) = 21.63 (2 d.p.)

Answer 2

   
$d= \sqrt{(x_1 -x_2)^2+(y_1-y_2)^2}= \\ \\ = \sqrt{(-4 -8)^2+(6-(-12))^2}= \\ \\ = \sqrt{(-4 -8)^2+(6+12)^2}= \\ \\ = \sqrt{(-12)^2+(18)^2}= \\ \\ = \sqrt{144+324}= \\ \\ =\sqrt{468}= \sqrt{4 \times 9 \times 13} = \\ \\ = 2\times 3 \sqrt{13} = 6\sqrt{13} =6\times 3.605551=21.63330\approx \boxed{21.63}$