
trapezoids have only two parallel sides
262 Chapter 6
There are some familiar things about
this shape
It’s a four-sided shape, but it only has one pair of parallel sides.
These parallel sides are called bases. We call this shape a
trapezoid.
A trapezoid
has exactly one
pair of opposite
parallel sides.
But what’s the area?
In theory, we could split the trapezoid into a rectangle and two
right triangles, and then add together the area of each shape. The
trouble is, we don’t have enough information to do this. We know
that they’re both right triangles, but we don’t know what the other
two angles are, and we only know the length of one of the sides. So
what can we do instead?
The bases here
are parallel.
Since the bases are
parallel, the angles
here are supplementary
(remember your F, N,
and Z patterns?).
24 meters
28 meters
53 meters
24 meters
…but we can’t work out the
area of the triangles because
we don’t know enough side
lengths.
We can split the trapezoid
into simpler shapes…