Can someone please help me with this?!?!!

Given: circle o, cd is diameter, chord ab || cd. arc ab = 74°, find arc ca.

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.

Acompany made a profit of 75000 over a period of 6 years on an initial investment of 15000 what is the annual roi