What is the equation of a circle with radius 4 and center (0,8)?

Question 5 spring semester final exam math evaluate

A)a square brown tarp has a square green patch green in the corner the side length of the tarp is (x + 8) and the side length of the patch is x what is the area of the brown part of the tarpb)a square red placemat has a gold square in the corner the side length of the gold square is (x - 2) inches with the width of the red region is 4 in what is the area of the red part of the placemat

Atriangle has side lengths of x, x+11, and 3x+5. what is the perimeter?