Thread: Linear functions and lines

Please help with the following question.

Abcd is a rectangle. Ab has equation x-2y+2=0 and c is the point (1,4).
1. Find the equations of cd and bc
2. Find the coordinates of the point b.

Any help with this would be greatly appreciated.

y = 1/2 x + 1

The line cd is parallel to the line Ab so the gradients are equaled:

SO for line cd we have y = 1/2 x + c.. now we substitute (1,4)

4 = 1/2(1)+c --> c= 7/2. --> y = 1/2 x + 7/2...

For line bc the line intersects at a right angle use this property to find the equation....

Thank you very much I had a problem with the gradient and clearly it threw the rest of my calcs off.