About Perimeter

1. The perimeter is the total
distance around the outside
of a 2D shape. You calculate
it by adding together all the
lengths of a shape.

2. How To Calculate The
Perimeter Of A Rectangle
Because a rectangle is a shape that
has two pairs of equal parallel
sides there are several other ways
to work this out:
- You could add 5cm and 12cm
then multiply bay 2 or
- You could multiply 5cm by 2 and
multiply 12cm by 2 then add the
totals. 12cm
5cm 5cm
12cm
The perimeter = 12cm +5cm+12cm+5cm
= 34cm

3. Have a Go : Level 1
5cm
30cm
30cm
5cm
answer =

4. 15cm
13 cm