I need to find angle C, side length AB and side length AC

5/6+7/8what is the answer sealsdbdbshd

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.

What ia the sum if the first 7 terms of the geometric series