Prealgebra

# Key Terms

PrealgebraKey Terms

### Key Terms

angle
An angle is formed by two rays that share a common endpoint. Each ray is called a side of the angle.
area
The area is a measure of the surface covered by a figure.
complementary angles
If the sum of the measures of two angles is $90°90°$, then they are called complementary angles.
cone
A cone is a solid figure with one circular base and a vertex.
cube
A cube is a rectangular solid whose length, width, and height are equal.
cylinder
A cylinder is a solid figure with two parallel circles of the same size at the top and bottom.
equilateral triangle
A triangle with all three sides of equal length is called an equilateral triangle.
hypotenuse
The side of the triangle opposite the 90° angle is called the hypotenuse.
irregular figure
An irregular figure is a figure that is not a standard geometric shape. Its area cannot be calculated using any of the standard area formulas.
isosceles triangle
A triangle with two sides of equal length is called an isosceles triangle.
legs of a right triangle
The sides of a right triangle adjacent to the right angle are called the legs.
perimeter
The perimeter is a measure of the distance around a figure.
rectangle
A rectangle is a geometric figure that has four sides and four right angles.
right triangle
A right triangle is a triangle that has one $90°90°$ angle.
similar figures
In geometry, if two figures have exactly the same shape but different sizes, we say they are similar figures.
supplementary angles
If the sum of the measures of two angles is $180°180°$, then they are called supplementary angles.
trapezoid
A trapezoid is four-sided figure, a quadrilateral, with two sides that are parallel and two sides that are not.
triangle
A triangle is a geometric figure with three sides and three angles.
vertex of an angle
When two rays meet to form an angle, the common endpoint is called the vertex of the angle.