A and C are the opposite vertices of a square ABCD, and have
coordinates (a,b) and (c,d), respectively. What are the coordinates
of the vertices B and D? What is the area of the square?
A 1 metre cube has one face on the ground and one face against a
wall. A 4 metre ladder leans against the wall and just touches the
cube. How high is the top of the ladder above the ground?
Is there a relationship between the coordinates of the endpoints of a line and the number of grid squares it crosses?
Working through the interactivity should help you with this. It
is also worth going back to the first page of the interactivity and
trying out your ideas there.
There are several possible approaches to the final problem: