/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 67 What are the dimensions of a rec... [FREE SOLUTION] | 91Ó°ÊÓ

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What are the dimensions of a rectangular tract of land when its perimeter is 44 kilometers and its area is 120 square kilometers?

Short Answer

Expert verified
The dimensions of the land are either 10 km by 12 km or 12 km by 10 km

Step by step solution

01

Write out the formulas representing the given

Let the length of the rectangular land be \(L\) km and the width be \(W\) km. Given that the perimeter is 44 km, we can write \(2(L + W) = 44\). Given that the area is 120 sq km, we can write \(L * W = 120\)
02

Simplify the perimeter equation

When you divide the equation \(2(L + W) = 44\) by 2, you get \(L + W = 22\)
03

Solve for one variable

Let's solve for \(L\). From the equation \(L + W = 22\), we find \(L = 22 - W\)
04

Substitute into the Area equation

Substitute \(L = 22 - W\) into the area equation \(L * W = 120\) and solve for \(W\). This gives \((22 - W) * W = 120\), which simplifies to \(W^2 - 22W + 120 = 0\)
05

Solve quadratic equation

The equation \(W^2 - 22W + 120 = 0\) is a quadratic equation and can be factored to \((W-10)(W-12) = 0\). Solving for \(W\), we get two possible solutions \(W = 10\) km and \(W = 12\) km
06

Solve for Length

By substituting \(W = 10\) km and \(W = 12\) km into \(L = 22 - W\) we get respective lengths of \(L = 12\) km and \(L = 10\) km. Thus, there are two possible dimensions: \(10km \times 12km\) or \(12km \times 10km\)

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Quadratic Equations
Understanding quadratic equations is fundamental to many branches of mathematics, including geometry. A quadratic equation is an equation of the second degree, meaning it includes at least one term that is squared. The standard form of a quadratic equation is \(ax^2 + bx + c = 0\), where \(a\), \(b\), and \(c\) are coefficients and \(x\) represents the unknown variable.

The solutions to a quadratic equation are also known as the 'roots', and there are a few methods for solving it. One can use factoring, completing the square, or the quadratic formula to find the roots. In the context of geometric applications, these quadratic equations often arise when dealing with the properties of geometric shapes, such as the area of rectangles, as seen in the problem provided. Factoring, as was done in the step-by-step solution \(W^2 - 22W + 120 = 0\) to \( (W-10)(W-12) = 0\), is a way to find potential values of \(W\) that satisfy both the area and perimeter constraints for the rectangle.
Geometric Applications of Algebra
Algebra can be visualized beautifully through its geometric applications, especially in problems involving perimeter and area. When tackling a question like determining the dimensions of a land tract, algebraic equations are derived from geometric formulas. For example, the formula for perimeter of a rectangle, which is \(P = 2(L + W)\), where \(P\) is the perimeter, \(L\) is the length, and \(W\) is the width.

To find the dimensions based on a given perimeter or area, one must translate the geometric properties into algebraic expressions. Then, using algebraic methods, solve for the unknowns. The exercise solution illustrates this process by first setting up equations based on the known perimeter and area and eventually reducing the problem down to a quadratic equation \(W^2 - 22W + 120 = 0\), which is then solved to find the dimensions of the land.
Perimeter and Area Relationships
In geometry, the perimeter and area are fundamental attributes of shapes that have distinct relationships. The perimeter of a shape is the total length of its boundary, while the area represents the extent of the shape's surface. For rectangles, the perimeter is the sum of all sides, \(P = 2(L + W)\), whereas the area is the product of its length and width \(A = L \times W\).

Problems that involve both perimeter and area simultaneously often lead to systems of equations that can be solved algebraically. The relationship between these two properties is evident in the provided exercise where the perimeter and area are given, and they together form a system that, when solved, reveals the dimensions of the rectangle. The exercise also demonstrates how algebra is used to express and solve these geometric relationships, culminating in a straightforward solution to what initially seems to be a complex problem.

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