The diameter of a circle is 9 feet. find the radius.

What is sin 7x/4 ? i need on this urgent trig

The function a represents the cost of manufacturing product a, in hundreds of dollars, and the function b represents the cost of manufacturing product b, in hundreds of dollars. a(t) = 5t + 2 b(t) = 7t - 2t +4 find the expression that describes the total cost of manufacturing both products, a(t) + b(t). a. 7t^2 - 7t + 2 b. 7t^2 + 3 +6 c. 7t^2 + 7t - 6 d. 7t^2 - 3t + 6

What is the image of c for a 90° counterclockwise rotation about a? (3, 7) (-1, 3) (7, 3)