Middle Measurement Unit Key Vocabulary

Unit Key Vocabulary Acute triangle – a triangle where all three angles are acute (less than 90°) Area – the measure of the size of the surface of a two-dimensional figure; measured in square units Base – side of a plane figure or face of a solid, particularly one perpendicular to the direction height is measured Complex shape – a figure that includes the elements of two or more simple shapes (triangles, rectangles, squares, circles) Cubic centimeter – the volume equal to a cube one centimeter on each side Cubic foot – the volume equal to a cube one foot on each side Cubic inch – the volume equal to a cube one inch on each side Cubic unit – a unit of measurement of volume or capacity Edge – a line segment joining two adjacent vertices in a two-dimensional figure or a shared boundary between two faces of a three-dimensional figure Equilateral triangle – triangle in which all three sides are equal in length Face – a flat surface of a three dimensional figure Height – the perpendicular distance of a two- or three- dimensional shape from the base to the opposite vertex Length – a measurement of the distance from one point to another Net – a flattened three-dimensional figure that can be turned into a solid by folding it Obtuse triangle – a triangle that has one internal angle greater than 90° Quadrilateral – a polygon that has four sides Parallel lines – two lines that lie in the same plane and maintain the same distance apart over their entire length, and never intersect Rectangle – a quadrilateral (four-sided figure) with four right angles Rectangular prism – a three-dimensional figure of which all faces are rectangles Right angle – an angle of exactly 90° Right triangle – a triangle containing an angle of 90° Square – a rectangle with four congruent sides Square foot – the area equal to a square one foot on each side Square inch – the area equal to a square one inch on each side Square meter – the area equal to a square one meter on each side Square unit – a unit of measurement of area Surface area – the total area of all the faces or surfaces of a three-dimensional figure Trapezoid – a quadrilateral that has exactly one pair of parallel sides Vertices – plural for vertex, the common point where two sides or edges meet Volume – a measure of the number of cubic units needed to fill the space inside an object Width – the minimum distance between parallel lines of a figure