Example: The sum of 5 and 6 is 11.SURFACE AREA the sum of the areas of each face of a three-dimensional figure SYSTEM OF
EQUATIONS two or more equations, generally with two or more variables Example: x + 2y =
9
x + 4y = 20
TANGENT LINE Tangent means intersecting at one point. A line tangent to a circle intersects
exactly one point on the circumference of the circle. Two circles that touch at only one point are
also tangent. A tangent line to a circle is always perpendicular to the radius drawn to that point
of intersection.
UNDEFINED An equation is undefined when it involves the square root of a negative number
(imaginary) or dividing by 0.
VARIABLE an unknown quantity, usually represented by a letter such as x, y, a, b, etc.
VERTEX In plane geometry, the corners of a shape. For example, a triangle has three vertices.
In coordinate geometry, the vertex of a parabola is the “trough” of the graph.
VOLUME the amount of space a three-dimensional object displaces (as in the air or water) XY-
PLANE another name for the coordinate plane; a Cartesian system of two axes: horizontal (x)
and vertical (y)