Area of Rectangle

Area = length × width

Use the formula for the area of a rectangle.

Area | = | length × width |

| = | 10 feet × 4 feet |

| = | 40 square feet |

The area of the rectangle is 40 square feet.

Use the given information to set up an equation and solve for the width.

| Area | = | length × width |

9 times some number equals 45 | 45 sq ft | = | 9 ft × width |

related division: 45 ÷ 9 = 5 | 45 sq ft | = | 9 ft × 5 ft |

So, the width of the rectangle is 5 feet.