To find slope, y2-y1/x2-x1
9-6/-3-(-9)=
3/6= 1/2
Slope = 1/2.
Y=1/2x.
A diagonal of a rectangle cuts the rectangle into 2 right triangles with sides equal to the sides of the rectangle and with a hypotenuse that is the diagonal. All you need to do is use the pythagorean theorem: where a and b are the sides of the rectangle and c is the length of the diagonal.