Dana’s new bike cost $180. Her parents agree to pay 60% of the cost if she will pay the rest. How much money will Dana need to save to help pay for the new bike?

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