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Which is an equation for the nth terms of the sequence 12,15,18,21

Adecorative window is made up of a rectangle with semicircles at either end. the ratio of ad to ab is 3: 2 and ab is 30 inches. what is the ratio of the area of the rectangle to the combined area of the semicircles? possible answers: a. 2: 3 b. 3: 2 c. 6: π d. 9: π e. 30: π

Graph the equationy= x+3[tex]y = x + 3[/tex]