12 Questions Semicircles: Area, Perimeter, Diameter – MATH Know the formulas for the area and circumference of a circle and use them to solve problems. Based on Common Core CC Standard 7.G.B.4 Which is the formula that would be used to calculate the perimeter of a semicircle? πr² ½πd + d π² 2πr Which is the formula that would be used to calculate the area of a semicircle? (πr²)/2 πr² 2πr 2πr²/2 What is the definition of diameter? The distance from the center of a circle to one side. The distance once around the circle. A line straight across a circle, through the center. Adding all the sides of the circle. … and 9 more awesome questions! Check them out by clicking “Play”.