The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².

The surface area of a cube is (2 x length x width) + (2 x width x height) + (2 x length x height):

sa = 2lw + 2wh + 2lh
sa = (2 x 8 x 6) + (2 x 6 x 3) + (2 x 8 x 3)
sa = (96) + (36) + (48)
sa = 180

An equation is two expressions separated by an equal sign. The key to solving equations is to repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.

A trapezoid is a quadrilateral with one set of parallel sides.

The volume of a cube is height x length x width:

v = h x l x w
v = 7 x 4 x 5
v = 140