幅 — 定義、公式と例

Width — Definition, Formula & Examples ✕ Browse by Letter A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Browse by Subject Algebra Geometry Trigonometry Pre-Calculus Calculus Statistics & Probability Arithmetic & Numbers Sets, Logic & Proofs Advanced Topics Browse by Grade Middle School Math Pre-Algebra Algebra 1 Algebra 2 SAT Math AP Calculus AP Statistics Explore Tools & Calculators Practice Problems Formula Sheets Comparisons Width — Definition, Formula & Examples Width is the distance from one side of an object to the other, measured horizontally or along the shorter dimension. It tells you how wide something is. Width is a linear measurement representing the extent of a figure or object along its shorter lateral dimension, perpendicular to its length. Key Formula A = l × w A = l \times w A = l × w Where: A A A = Area of the rectangle l l l = Length (the longer side) w w w = Width (the shorter side) How It Works To find the width of an object, measure straight across from one side to the opposite side. Use a ruler, tape measure, or other measuring tool. Width is one of the key measurements used to calculate area and volume. For a rectangle, you multiply length times width to find the area. For a box (rectangular prism), you multiply length times width times height to find the volume. Worked Example Problem: A garden is 8 feet long and 5 feet wide. What is its area? Identify measurements : The length is 8 feet and the width is 5 feet. l = 8 ft , w = 5 ft l = 8 \text{ ft}, \quad w = 5 \text{ ft} l = 8 ft , w = 5 ft Multiply length by width : Use the area formula for a rectangle. A = 8 × 5 = 40 ft 2 A = 8 \times 5 = 40 \text{ ft}^2 A = 8 × 5 = 40 ft 2 Answer: The garden has an area of 40 square feet. Why It Matters You use width every time you measure furniture to see if it fits through a door, figure out how much paint covers a wall, or calculate the area of a room. It is one of the first measurements taught in geometry and stays essential through advanced math and trades like carpentry and engineering. Common Mistakes Mistake: Confusing width with length and swapping them in a formula. Correction: For rectangles, the area formula gives the same result either way since multiplication is commutative. However, keeping width as the shorter side and length as the longer side helps you communicate measurements clearly and avoid errors in real-world problems. Feedback