What is the area of a rectangle with length 12 and width 8?

Area of a rectangle = length × width = 12 × 8 = 96 square units. Memorize basic geometry formulas: (1) Rectangle area = l × w, perimeter = 2(l + w); (2) Square area = s², perimeter = 4s; (3) Triangle area = ½ × base × height; (4) Circle area = πr², circumference = 2πr; (5) Parallelogram area = base × height; (6) Trapezoid area = ½(b₁ + b₂) × h. Perimeter sums the lengths around the boundary; area measures the surface inside. Volume formulas: rectangular prism = l × w × h; cylinder = πr²h; sphere = (4/3)πr³; cone = (1/3)πr²h. Units: area is in square units (sq ft, sq m, etc.); volume in cubic units; perimeter in linear units. The ASVAB MK includes several geometry questions; formula recognition is essential.