Chapter 7: Problem 27
Find the area triangle formed by the given three points. \((1,1),(2,3),\) and (3,3)
Short Answer
Expert verified
The area of the triangle is 1 square unit.
Step by step solution
01
Identify the formula for the Area of a Triangle
The area of a triangle given its vertices \(x_1, y_1\), \(x_2, y_2\), and \(x_3, y_3\) can be calculated using the determinant formula: \[ Area = \frac{1}{2} \, | x_1(y_2-y_3) + x_2(y_3-y_1) + x_3(y_1-y_2) | \]
02
Substitute the given points into the formula
Substitute the points \(1,1\), \(2,3\), and \(3,3\) into the formula to find the area: \[ Area = \frac{1}{2} \, | 1(3-3) + 2(3-1) + 3(1-3) | \]
03
Simplify the expression within the absolute value
Calculate the expression inside the absolute value: \[ 1(3-3) = 0, \quad 2(3-1) = 4, \quad 3(1-3) = -6 \]Adding them gives: \[ 0 + 4 - 6 = -2 \]
04
Calculate the absolute value and the area
The absolute value of \(-2\) is \(|-2| = 2\). Thus, the area is: \[ Area = \frac{1}{2} \times 2 = 1 \]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Area of a Triangle
The area of a triangle is a fundamental concept in geometry. It refers to the amount of space enclosed by the three sides of a triangle. In coordinate geometry, where the triangle is defined by the position of its three vertices, calculating the area becomes a straightforward task using a formula derived from the coordinates. You're essentially working with the vertices' coordinates to form a plane on which the area can be easily calculated.
The specific formula we use in this context is:
Using the absolute value ensures that the area is always positive, as it should be a numerical representation of space. Calculating the area this way helps in determining the space no matter how the vertices are ordered; you're always assured of an accurate, positive result.
The specific formula we use in this context is:
- \ Area = \frac{1}{2} \, | x_1(y_2-y_3) + x_2(y_3-y_1) + x_3(y_1-y_2) | \
Using the absolute value ensures that the area is always positive, as it should be a numerical representation of space. Calculating the area this way helps in determining the space no matter how the vertices are ordered; you're always assured of an accurate, positive result.
Determinant Formula
The determinant formula is a mathematical tool that you'll often encounter in linear algebra. It's especially handy here in finding the area of a triangle based on its vertices' coordinates.
Think of the determinant as a way to encase the calculations required to find the area based on where the vertices lie on a plane. By using this method, you're methodically adjusting the values based on each pair of coordinates.
Think of the determinant as a way to encase the calculations required to find the area based on where the vertices lie on a plane. By using this method, you're methodically adjusting the values based on each pair of coordinates.
- The core of the formula involves multiplying coordinates in a specific manner: \ x_1(y_2-y_3) + x_2(y_3-y_1) + x_3(y_1-y_2) \
- The absolute value ensures correctness in measurement, avoiding negative area results which don't have practical meaning.
- Finally, multiplying by \(\frac{1}{2}\) scales the value down to accurately reflect the triangle’s area in the coordinate plane.
Coordinate Geometry
Coordinate geometry, or analytic geometry, is a fascinating field that merges algebra and geometry by placing shapes within a coordinate system. This allows for a more rigorous understanding of spatial relationships. With triangles, understanding their shape and size through their vertices is particularly useful.
In coordinate geometry, you can plot points on a Cartesian plane, defined by \(x, y\) coordinates. This direct representation allows us to calculate properties like lengths, angles, and areas using algebraic formulas. For our purpose:
In coordinate geometry, you can plot points on a Cartesian plane, defined by \(x, y\) coordinates. This direct representation allows us to calculate properties like lengths, angles, and areas using algebraic formulas. For our purpose:
- We use the coordinates of points like \(1,1\), \(2,3\), and \(3,3\) to determine various parameters.
- The ability to use algebraic techniques to perform geometric operations simplifies complex calculations like area finding.
- This approach is elegant and efficient for tracing and understanding patterns or specific characteristics of a shape.
Vertices of a Triangle
In geometry, especially when working with coordinate systems, vertices play a pivotal role in defining a shape. A triangle's vertices are its three distinct points which form its corners and dictate its size and shape.
For a triangle on a coordinate plane, vertices \(x_1, y_1\), \(x_2, y_2\), and \(x_3, y_3\) are crucial:
For a triangle on a coordinate plane, vertices \(x_1, y_1\), \(x_2, y_2\), and \(x_3, y_3\) are crucial:
- They determine the triangle's orientation and overall geometry.
- These points are used in the determinant formula to compute the precise area of the triangle.
- Knowing the exact locations of the vertices allows you to explore additional properties like perimeter and centroid placement.