How_To_Be_Good_At_Math

quadrilaterals Angles inside

Angles inside

quadrilaterals

Quadrilaterals have different names, depending on the properties

of their sides and angles. We looked at a quadrilateral's sides on

pages 216-17. Now let's have a closer look at its angles.

Types of quadrilateral

Quadrilaterals are polygons with four sides and

four angles. Here are some of the quadrilaterals

we see most often in geometry.

Non-parallel

sides can be

the same or

different lengths

Opposite sides are

equal lengths

All four sides

are equal

All four angles

are right angles

Dashes mark

sides of equal

length

Trapezium

Two of a trapezium‘s angles are

greater than 90°. It has one pair of

parallel sides.

Parallelogram

A parallelogram has two pairs of

equal angles, opposite to each other.

Square

A square is special kind of rectangle,

with four right angles and four equal sides.

Rectangle

A rectangle has four right angles

and two pairs of equal, parallel sides.

Rhombus

The opposite angles of a rhombus

are equal. Another name for a rhombus

is a diamond.

All quadrilaterals have

four angles, four sides,

and four vertices.

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