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Exemplo 9.29 de Prealgebra, 9.4 Use Properties of Rectangles, Triangles, and Trapezoids
Use Properties of Rectangles, Triangles, and Trapezoids: exemplo 9.29
Problema e solução em inglês, como no livro original.
The width of a rectangle is two inches less than the length. The perimeter is inches. Find the length and width.
Resolva no papel primeiro. Depois abra a solução um passo de cada vez e pare assim que conseguir terminar sozinho.
Solução
Step 1. Read the problem. Step 2. Identify what you are looking for. the length and width of the rectangle Step 3. Name. Choose a variable to represent it.
Now we can draw a figure using these expressions for the length and width.Since the width is defined in terms of the length, we let L = length. The width is two feet less that the length, so we let L − 2 = width Step 4.Translate.
Write the appropriate formula. The formula for the perimeter of a rectangle relates all the information.
Substitute in the given information.Step 5. Solve the equation. Combine like terms. Add 4 to each side. Divide by 4. The length is 14 inches. Now we need to find the width. The width is L − 2.
The width is 12 inches.Step 6. Check:
Since , this works!Step 7. Answer the question. The length is 14 feet and the width is 12 feet.
Sua vez
O Try It do livro logo depois deste exemplo: mesma ideia, outros números. Só a resposta é dada.
The width of a rectangle is seven meters less than the length. The perimeter is meters. Find the length and width.
Como foi?