What is the perimeter of the rectangle?

The figure is an L-shape made of 4 unit squares.

$$\text{Area} = 4 \ \text{square units}$$

perimeter = $4 \times$ (number of squares) $- 2 \times$ (number of shared edges).
Number of squares = 4.
Number of shared edges = 3.

$$\text{Perimeter} = 4 \times 4 - 2 \times 3 = 16 - 6 = 10 \ \text{units}$$

Area = 4 square units, Perimeter = 10 units

Area = 4 square units, Perimeter = 10 units

Number 4

The figure is a single blue square (1 unit square).

$$\text{Area} = 1 \ \text{square unit}$$

All 4 sides are external.

$$\text{Perimeter} = 4 \ \text{units}$$

Area = 1 square unit, Perimeter = 4 units

Area = 1 square unit, Perimeter = 4 units

Number 5

The figure is a 2 by 2 square (4 unit squares).

$$\text{Area} = 4 \ \text{square units}$$

perimeter = $4 \times 4 - 2 \times 4 = 16 - 8 = 8$ units (4 shared edges).
Or 2(length + width) = 2(2 + 2) = 8 units.

$$\text{Perimeter} = 8 \ \text{units}$$

Area = 4 square units, Perimeter = 8 units

Area = 4 square units, Perimeter = 8 units

Number 6

The figure is a straight line of 5 unit squares.

$$\text{Area} = 5 \ \text{square units}$$

4 ends + 2 sides along length $\times 5$, but using formula.
Number of shared edges = 4.

$$\text{Perimeter} = 4 \times 5 - 2 \times 4 = 20 - 8 = 12 \ \text{units}$$

Area = 5 square units, Perimeter = 12 units

Area = 5 square units, Perimeter = 12 units

Number 7

The figure has 6 unit squares (e.g., 2x3 rectangle).

$$\text{Area} = 6 \ \text{square units}$$

number of shared edges = 7.

$$\text{Perimeter} = 4 \times 6 - 2 \times 7 = 24 - 14 = 10 \ \text{units}$$

Area = 6 square units, Perimeter = 10 units

Area = 6 square units, Perimeter = 10 units