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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