Definition of Terms, Continued
Quadrilaterals
Quadrilaterals are plane figures bound by four straight sides. Four-sided
figures with parallel opposing sides are further classified as parallelograms.
A parallelogram having four equal sides and equal angles is called a square.
A rhombus has four equal sides and equal opposing angles. A figure with
equal opposing sides and equal angles is a rectangle. A figure with equal
opposing sides and equal opposing angles is a rhomboid. Quadrilaterals with
only two parallel sides and no angles equal are trapezoids. If no sides and no
angles are equal or parallel, the figure is called a trapezium. Trapezoids and
trapeziums are quadrilaterals but are not parallelograms.
Figure 2-5 shows the six different types of quadrilaterals.
Figure 2-5.—Quadrilaterals.
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