Question

Triangle ABC has been rotated 90° to create triangle DEF. Using the image below, prove that perpendicular lines have opposite and reciprocal slopes. You must show all of your work to receive credit.

Answer 1

Help Me @ganeshie8 @mathmale

Answer 2

I do know that were going to need slope formula m = y*2 - y*1 / x*2 - x*1

Answer 3

Exactly ! Notice that the lines BC and EF are perpendicular as the second triangle is obtained by rotating the first triangle by 90 degrees.

So you can do below :
1) Find the slope of CB
2) Find the slope of FE
3) Conclude by saying that the slopes are reciprocals of each other and opposite in sign