Help i don't know what to do

What other information do you need to prove triangle dac=bca by asa

Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b

Perry observes the opposite parallel walls of a room in how many lines do the plains containing the walls intersect