[The narrator reads out the onscreen text.]

NARRATOR: Question two. Find the distance between the points A (1, 2) and B (13, 7).

[On a graph, the horizontal x axis is marked from 0 to 16. The vertical y axis is marked from 0 to 10. A diagonal red line runs from point A (1, 2) to point B (13, 7). Dotted lines run from points A and B to point C (13, 2), forming a right-angled triangle.]

NARRATOR: First, plot the points and form the right-angled triangle ABC. AC is equal to 12. BC is equal to 5. By Pythagoras's theorem, AB squared is equal to 12 squared plus 5 squared, which is equal to 144 plus 25, which is equal to 169. Therefore, AB is equal to the square root of 169, which is 13. So the distance between the points A and B is 13.