1. The equation of a circle is pi*r^2 = A, with the Area a function of the radius. Plug r into the equation, or A to get the answers in the table.
4.1 Draw a line between the points, and extending on into infinity on both sides.
4.2 pick any 2 of the points, and put it into this, (y1-y2)/(x1-x2), or the equation for slope based on two points. As point one being (x1, y1) and point two being (x2, y2), the fraction is then the slope.
4.3 The slope you will get is -1, which means that the rectangle would be a square. and the length and width would be equal.