Geometry

The area of a space is the amount of space it covers measured in square units, such as square centimeters or square inches. One way to measure the area of a shape is to count the number of square units it covers. To find the area of a square or rectangle, multiply the length by the width. Area of a square = side x side = s x s. Area of a rectangle = length x width = l x w = lw.

Area of a Triangle

The area of triangle = ½ base x height = ½ bh. The area of a parallelogram, split it into two identical triangles (base x height = bh).

Circle and Compound Figures

The radius of a circle is designated with an r. to find the area of a circle, multiply 3.14 x r x r. Compound figures are shapes created by combining two or more polygons. To find the area, divide it into shapes with known areas such as triangles, circles, and squares. Then, find the area of each shape and add or subtract.

Space Figures

Space figures are figures whose points are in one or more plane. Cubes and cylinders are examples. A prism has two identical, parallel bases. All of the faces on a rectangular prism are rectangles. A cube is a prism with six identical, square faces. A pyramid is a space figure whose base is a polygon and whose faces are triangles with a common vertex-the point where two rays meet. A cylinder has a curved surface and two parallel bases that are identical circles. A cone has one circular, flat face and one vertex. A sphere has no flat surface. All points are an equal distance from the center.

Volume of a Box

The volume of a 3-D shape is the amount of space it occupies. Volume is measured in cubic unites, such as cubic centimeters or cubic inches. The formula for finding the volume of a box is length times width times height (L x W XH). The answer is given in cubic units.

Volume of a Cylinder, Pyramid, and Sphere

To find the volume of a cylinder, take the area of the base x height or (3.14xrxrxh). To find the volume of a pyramid, take the area of the base x height x 1/3 or (1/3Ah). To find the volume of a sphere, take 4/3x3.14xrxrxr.