1. Perimeter
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2. Perimeter (P)- the distance around a closed figure.
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3. P = ? 16 cm Perimeter 4 × 4 cm = 16 cm 4 cm 4 cm 4 cm 4 cm
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4. P = ? 23 cm Perimeter 4 cm 7 cm 7 cm 4 cm 7 cm + 7 cm + 4 cm + 4 cm =
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5. P = 24 cm ? Perimeter 8 × 3 cm = 24 cm 3 cm 3 cm 3 cm 3 cm 3 cm 3 cm
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6. P = ? 24 cm Perimeter 10 cm 8 cm 6 cm 8 cm + 6 cm + 10 cm = 24 cm
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7. P = ? 24 cm Perimeter 4 cm 4 cm 5 cm 5 cm 6 cm 5 cm + 5 cm + 4 cm +
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8. P = ? 22 cm Perimeter 4 cm 5 cm 5 cm 8 cm 5 cm + 5 cm + 4 cm + 8 cm =
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9. Your Turn! P = 10 cm ? P = 12 cm ? P = 18 cm ? P = 16 cm ? P = 24 cm ?

10. Length (ℓ)- a side (usually the bottom) of a polygon.
Length and Width
Length (ℓ)- a side (usually the bottom) of a polygon.
Width (w)- the measurement of a perpendicular line drawn from the length to the top of the polygon.
Perpendicular Lines w w ℓ ℓ w w ℓ ℓ

11. Perimeter of Squares P = 4 × 1 cm P = 4 cm P = 4 × 3 cm P = 12 cm P =
Since the length (ℓ) of a square is congruent with all other sides, if you know the length of just one side, you can find the perimeter (P) for the entire square.
You can add the length 4 times.
P = ℓ+ ℓ + ℓ + ℓ
Or you can multiply the length of the base by 4.
P = 4 ℓ P = 4 ×
1 cm
1 cm P =
4 cm
3 cm P = 4 ×
3 cm P =
12 cm
4 cm P = 4 ×
4 cm P =
16 cm
© 2007 M. Tallman

12. Perimeter of Rectangles
Since rectangles have two congruent sides, if you know the length (ℓ) and the width (w) you can find the perimeter (P) for the entire rectangle.
You can add to find the perimeter…
P = ℓ + w + ℓ + w
…or you can multiply and add.
P = 2 × (ℓ + w)
1 cm P =
2 ×
(4 cm + 1 cm)
4 cm P = 2 ×
5 cm
P = 10 cm
5 cm
3 cm P =
2 ×
(5 cm + 3 cm) P = 2 ×
8 cm
P = 16 cm P = 2 ×
(6 cm + 4 cm)
4 cm P = 2 ×
10 cm
P = 20 cm
6 cm
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13. Your Turn! 4 ft 12 ft P = 2 × ( 12 ft + 4 ft ) P = 2 × 16 ft P = 32 ft
Use the formula P = ℓ + ℓ + w + w or P = 2 × (ℓ + w) to find the perimeter of the rectangle.
4 ft
12 ft P = 2 × (
12 ft +
4 ft ) P = 2 ×
16 ft P = 32 ft
© 2007 M. Tallman

14. Your Turn! 9 cm 11 cm P = 2 × ( 9 cm + 11 cm ) P = 2 × 20 cm P = 40 cm
Use the formula P = ℓ + ℓ + w + w or P = 2 × (ℓ + w) to find the perimeter of the rectangle.
9 cm P = 2 × (
9 cm +
11 cm ) P = 2 ×
20 cm P = 40 cm
11 cm
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15. Your Turn! 7 yd 7 yd P = 4 × 7 yd P = 28 yd
Use the formula P = ℓ + ℓ + w + w or P = 2 × (ℓ + w) to find the perimeter of the rectangle. P = 4 ×
7 yd P = 28 yd
7 yd
7 yd
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16. Your Turn! 4 in 3 in P = 2 × ( 3 in + 4 in ) P = 2 × 7 in P = 14 in
Use the formula P = ℓ + ℓ + w + w or P = 2 × (ℓ + w) to find the perimeter of the rectangle. P = 2 × (
3 in +
4 in ) P = 2 ×
7 in P = 14 in
4 in
3 in
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17. Your Turn! 1 m 7 m P = 2 × ( 7 m + 1 m ) P = 2 × 8 m P = 16 m
Use the formula P = ℓ + ℓ + w + w or P = 2 × (ℓ + w) to find the perimeter of the rectangle.
1 m
7 m P = 2 × (
7 m +
1 m ) P = 2 ×
8 m P = 16 m
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