Given trapezoid pqrs, which of the following must be true?
both pairs of opposite sides are parallel.
the legs are congruent to each other.
one pair of opposite sides must be congruent.
one pair of opposite sides must be parallel.

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.