Find the distance between the points (0, 0) and (36, 15). Can you now find the distance between the two towns A and B discussed in Section 7.2.

By formula,

Distance between two points (D) = $\sqrt{(y$2 - y1)^2 + (x2 - x1)^2}

Substituting values we get :

$\Rightarrow D = \sqrt{(15 - 0)^2 + (36 - 0)^2} \\[1em] = \sqrt{(15)^2 + (36)^2} \\[1em] = \sqrt{225 + 1296} \\[1em] = \sqrt{1521} \\[1em] = 39.$

The positions of towns A & B are given by (0, 0) and (36, 15), hence, as calculated above, the distance between town A and B will be 39 km.

Hence, distance between (0, 0) and (36, 15) is 39 units and distance between towns A and B = 39 km.