www.reference.com/article/formula-area-semicircle-6e3650e4493cb454

The area of a semicircle is (?*R*R)/2. This means the radius of the semicircle is squared, multiplied by the constant pi, then divided by 2.

www.reference.com/article/area-semicircle-ac74ac6fb847ce40

To find the area of a semicircle, use the formula 1/2(pi x r^2). You need the value of "r," or radius of the circle, and pi.

www.reference.com/article/determine-circumference-semicircle-e44c79f6976ca3d2

The perimeter of a semicircle is 1/2 of the circumference of the corresponding complete circle plus the diameter of the circle. The distance around the outside of a semicircle is generally called its perimeter.

www.reference.com/article/formula-circumference-circle-4e469956b137015d

The formula for the circumference of a circle is 2(pi)r. R stands for the radius of the circle, which can also be found by taking the diameter and dividing it by 2, and pi can be approximated by the decimal 3.14.

www.reference.com/article/formula-equation-a36486fa6ab80ab7

A formula equation is a visual representation of a reaction using chemical formulas. A chemical formula is an expression that states the number and types of atoms that make up any given molecule using the symbols for the elements and sub-scripted numbers.

www.reference.com/article/formula-concrete-mix-f2d173c79d82e26f

The formula for concrete mix is one part cement, two parts sand and three parts gravel or crushed stone. If hand mixing, it's inadvisable to exceed a water to cement ratio of 0.55, which translates to 55 pounds of water for every 100 pounds of cement.

www.reference.com/article/formula-cubic-feet-4185985608ff6e58

The cubic feet formula depends on the shape of the object for which one is calculating volume, but for a cube, v=a^3, where a is the length of one side in feet. For cylinders and prisms, the formula is the area of the base multiplied by the height.