What is the circumference of circle if the diameter is 21

Solve this problem! extra ! 3025/5.5 = a/90.75

Grace is standing 18 feet from a lighthouse and kelly is standing 10 feet from grace. the angle that grace looks up to see the top of the lighthouse is 45°. the angle that kelly looks up to see the top of the lighthouse is y°. find the height, h, of the lighthouse. find the angle, rounded to the nearest tenth of a degree, in which kelly looks up to the top of the lighthouse. to the nearest tenth of a degree, find the value of x° . in two or more sentences, explain your calculations

The balance of susu's savings account can be represented by the variable b. the inequality describing her balance b > $30 . which could be a solution to the inequality?