The length of a piece of yarn is 19.2 units. Jesse cut the piece of yarn into 4 smaller pieces that were all the same length. Which expression represents the length of each smaller piece of yarn?

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