1. The problem statement, all variables and given/known data How to rotate a triangle over a line? I have provided a attachment for it? 2. Relevant equations Y= mx +c I dont know the eq for reflection 3. The attempt at a solution My plan is find the eq of line. I have got points for the end points of the line but i dont know how to reflect the triangle over the line which is not straight. I searched the internet but i cant find any eq. Eq are provided for reflecting over x-axis, y-axis , over the line x=2 & over the line x=y but no equations are shown for rotating object over an oblique line. One site gave the method to find the eq of line which was used to rotate the triangle but it dont give any example for reverse case. Its link was: http://www.rcboe.org/cms/lib010/GA01903614/Centricity/Domain/1030/Reflections.pdf I have attached the figure. I want to rotate the triangle over the dark line. Some body please guide me. Zulfi.