To receive a grade a, the average of four 100-point exams must be 90 or better. if a student received scores of 89, 82, and 94 on the first three exams, what minimum score does he need on the fourth exam to earn an a?

Can someone me with this problem . show your work .

Describe the symmetry of the figure. identify lines of symmetry, if any. find the angle and the order of any rotational symmetry.

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.