What is the area of a rectangle that is 8 feet long and 5 feet wide?

Area of a rectangle = length × width = 8 × 5 = 40 square feet. Common geometry formulas tested on ASVAB: Rectangle area = L × W; Square area = side²; Triangle area = (1/2) × base × height; Circle area = π × radius² (use π ≈ 3.14 or 22/7). Rectangle perimeter = 2L + 2W; Square perimeter = 4 × side; Circle circumference = 2 × π × radius (or π × diameter). Watch units: linear measurements like perimeter are in regular units (feet, meters); area measurements are in square units (sq ft, sq m); volume is in cubic units (cu ft, cu m). Common mistake: confusing perimeter (length around) with area (space inside). For a rectangle: 8 ft long, 5 ft wide — perimeter = 2(8) + 2(5) = 26 ft; area = 40 sq ft. Real-world applications: flooring (area), fencing (perimeter), paint (area), trim (perimeter).