2. Calculate: a. The perimeter of a rectangle that is 20 cm long and 15 cm wide. b. The perimeter of a square with sides measuring 9 m . c. The perimeter of a regular hexagon, if each side is 7 cm . d. The perimeter of an equilateral triangle with each side measuring 12 mm .

To calculate the perimeters of the given shapes, we can use the following formulas: a. **Perimeter of a rectangle**: \[ P = 2 \times (length + width) \] For a rectangle that is 20 cm long and 15 cm wide: \[ P = 2 \times (20 \, \text{cm} + 15 \, \text{cm}) = 2 \times 35 \, \text{cm} = 70 \, \text{cm} \] b. **Perimeter of a square**: \[ P = 4 \times side \] For a square with sides measuring 9 m: \[ P = 4 \times 9 \, \text{m} = 36 \, \text{m} \] c. **Perimeter of a regular hexagon**: \[ P = 6 \times side \] For a regular hexagon with each side measuring 7 cm: \[ P = 6 \times 7 \, \text{cm} = 42 \, \text{cm} \] d. **Perimeter of an equilateral triangle**: \[ P = 3 \times side \] For an equilateral triangle with each side measuring 12 mm: \[ P = 3 \times 12 \, \text{mm} = 36 \, \text{mm} \] ### Summary of Results: - a. Perimeter of the rectangle: **70 cm** - b. Perimeter of the square: **36 m** - c. Perimeter of the regular hexagon: **42 cm** - d. Perimeter of the equilateral triangle: **36 mm**