How do you find missing dimensions of rectangles that only show the width?

To find missing dimensions of rectangles when only the width is provided, you typically need additional information, such as the area or the perimeter of the rectangle. If you know the area, you can divide it by the width to find the length. If you have the perimeter, you can use the formula ( P = 2(\text{length} + \text{width}) ) to solve for the length. Without additional information, you cannot determine the missing dimensions.