Perimeter of compound shapes

The Maths Habit

Ali says he walked all the way round the edge of the playground. Did he?

missed

No. He cut the corner. He missed two sides.

Perimeter
The distance all the way round the edge of a shape.
Side
A straight edge of a shape.
Compound shape
A shape made from two or more simple shapes.
Missing side
A side with no length written on it.

How many sides does each shape have?

A4 sides
B6 sides
C8 sides

5 cm2 cm3 cm3 cm8 cm5 cm
  1. Start at the dot.Follow the arrow.
  2. Go all the way round.Add each side as you pass it. Tick it.
  3. Stop back at the dot.Write the units: cm.
1Addside+side+side+ …
2Perimetercm

Work out the perimeter.

5 cm2 cm3 cm3 cm8 cm5 cm
1AddStart at the dot. Go all the way round.
5+2+3+3+8+5
2Perimeter26cm

Work out the perimeter.

6 cm9 cm3 cm5 cm3 cm4 cm
1AddStart at the dot. Go all the way round.
6+9+3+5+3+4
2Perimeter30cm

Work out the perimeter.

5 cm2 cm3 cm3 cm8 cm5 cm
1AddStart at the dot. Go all the way round.
5+2+3+3+8+5
2Perimeter26cm

Work out the perimeter.

10 cm3 cm4 cm3 cm6 cm6 cm
3 cm2 cm3 cm2 cm6 cm4 cm
1Add start at the dot, go all the way round2Perimeter write the units
1AddStart at the dot. Go all the way round.
10+3+4+3+6+6
2Perimeter32cm

Work out the perimeter.

5 cm2 cm3 cm3 cm8 cm5 cm
1AddStart at the dot. Go all the way round.
5+2+3+3+8+5
2Perimeter26cm

Work out the perimeter.

11 cm6 cm5 cm3 cm6 cm3 cm
3 cm2 cm3 cm2 cm6 cm4 cm
1Add start at the dot, go all the way round2Perimeter write the units
1AddStart at the dot. Go all the way round.
11+6+5+3+6+3
2Perimeter34cm

Work out the perimeter.

5 cm2 cm3 cm3 cm8 cm5 cm
1AddStart at the dot. Go all the way round.
5+2+3+3+8+5
2Perimeter26cm

Work out the perimeter.

7 cm12 cm3 cm5 cm4 cm7 cm
3 cm2 cm3 cm2 cm6 cm4 cm
1Add start at the dot, go all the way round2Perimeter write the units
1AddStart at the dot. Go all the way round.
7+12+3+5+4+7
2Perimeter38cm

Work out the perimeter of each shape.

3 cm2 cm3 cm2 cm6 cm4 cm
1Add start at the dot, go all the way round2Perimeter write the units
110 cm3 cm6 cm4 cm4 cm7 cm
1AddStart at the dot. Go all the way round.
10+3+6+4+4+7
2Perimeter34cm
26 m12 m3 m5 m3 m7 m
1AddStart at the dot. Go all the way round.
6+12+3+5+3+7
2Perimeter36m

The bar is 10 cm long. One part is 6 cm. How long is the other part?

10 cm6 cm?4 cm: 10 − 6 = 4

How long is the missing side?

5 cm9 cm44 cm: 9 − 5 = 4

3 cm4 cm10 cm6 cm63
  1. The two parts make the long side.Show why: slide them down.
  2. Missing part = long side − the other part.Do it across, then up.
  3. Write it on the shape.Then add all the sides.
1Missinglong side−part=
2Addside+side+side+ …
3Perimetercm

Work out the perimeter.

3 cm4 cm10 cm6 cm63
1Missing10−4=6
6−3=3
2AddStart at the dot. Go all the way round.
6+3+4+3+10+6
3Perimeter32cm

Work out the perimeter.

7 cm11 cm5 cm3 cm46
1Missing11−5=6
7−3=4
2AddStart at the dot. Go all the way round.
7+11+4+5+3+6
3Perimeter36cm

Work out the perimeter.

3 cm4 cm10 cm6 cm63
1Missing10−4=6
6−3=3
2AddStart at the dot. Go all the way round.
6+3+4+3+10+6
3Perimeter32cm

Work out the perimeter.

12 cm6 cm3 cm7 cm46
2 cm3 cm6 cm4 cm
1Missing long side − part2Add start at the dot, go all the way round3Perimeter write the units
1Missing12−6=6
7−3=4
2AddStart at the dot. Go all the way round.
12+4+6+3+6+7
3Perimeter38cm

Work out the perimeter.

3 cm4 cm10 cm6 cm63
1Missing10−4=6
6−3=3
2AddStart at the dot. Go all the way round.
6+3+4+3+10+6
3Perimeter32cm

Work out the perimeter.

10 cm7 cm4 cm5 cm53
2 cm3 cm6 cm4 cm
1Missing long side − part2Add start at the dot, go all the way round3Perimeter write the units
1Missing10−5=5
7−4=3
2AddStart at the dot. Go all the way round.
10+7+5+4+5+3
3Perimeter34cm

Work out the perimeter.

3 cm4 cm10 cm6 cm63
1Missing10−4=6
6−3=3
2AddStart at the dot. Go all the way round.
6+3+4+3+10+6
3Perimeter32cm

Work out the perimeter.

3 cm5 cm12 cm8 cm75
2 cm3 cm6 cm4 cm
1Missing long side − part2Add start at the dot, go all the way round3Perimeter write the units
1Missing12−5=7
8−3=5
2AddStart at the dot. Go all the way round.
7+3+5+5+12+8
3Perimeter40cm

Work out the perimeter of each shape.

2 cm3 cm6 cm4 cm
1Missing long side − part2Add start at the dot, go all the way round3Perimeter write the units
13 cm5 cm9 cm6 cm43
1Missing9−5=4
6−3=3
2AddStart at the dot. Go all the way round.
4+3+5+3+9+6
3Perimeter30cm
27 m12 m7 m3 m45
1Missing12−7=5
7−3=4
2AddStart at the dot. Go all the way round.
7+12+4+7+3+5
3Perimeter38m

Is the perimeter right? Thumbs up or thumbs down.

A8 cm3 cm4 cm3 cm4 cm6 cm
Perimeter = 28 cmRight
B3 cm4 cm10 cm6 cm
Perimeter = 23 cmWrong: 32 cm
C6 cm10 cm3 cm5 cm3 cm5 cm
Perimeter = 32 cmRight
D11 cm6 cm6 cm3 cm5 cm3 cm
Perimeter = 28 cmWrong: 34 cm

Perimeter of compound shapes worksheet, page 1

Perimeter of compound shapes worksheet, page 2

Answer sheet

  1. A rectangle has a perimeter of 30 cm. It is 9 cm long. How wide is it?

    6 cm

  2. A 3 cm by 2 cm corner is cut from a rectangle 10 cm by 6 cm. Work out the perimeter of the L shape left.

    32 cm

  3. Two squares with 4 cm sides are put side by side to make a rectangle. Work out its perimeter.

    24 cm

  1. Work out the perimeter. 1Missing10−6=46−3=32Add4+3+6+3+10+6

    Perimeter = 32 cm
    3 cm6 cm10 cm6 cm

  2. Work out the perimeter. 1Missing11−7=46−3=3

    Perimeter = 34 cm
    3 cm7 cm11 cm6 cm

  3. Work out the perimeter.

    Perimeter = 36 cm
    3 cm8 cm12 cm6 cm
Exit tickets to print