Chapter 3: Problem 32
Find the area of the triangle with the given vertices. $$(1,1),(-1,1),(0,-2)$$
Short Answer
Expert verified
The area of the triangle with the vertices \((1,1)\), \((-1,1)\), and \((0,-2)\) is \(3\) square units.
Step by step solution
01
Understand and Apply the Formula
The Area Formula of a Triangle Given the Three Vertices is:\[Area = \frac{1}{2} \left| x_1(y_2-y_3) + x_2(y_3-y_1) + x_3(y_1-y_2) \right|\]where \((x_1,y_1)\), \((x_2,y_2)\), and \((x_3,y_3)\) are the coordinates of the vertices of the triangle. In this case, the vertices are \((1,1)\), \((-1,1)\), and \((0,-2)\). So, substitute the given coordinates into the formula.
02
Substitute the Coordinates
We now replace the variables \(x_1\), \(y_1\), \(x_2\), \(y_2\), \(x_3\), and \(y_3\) with the given coordinates:\[Area = \frac{1}{2} \left| 1 \times (1 - (-2)) + (-1) \times ((-2) - 1) + 0 \times (1 - 1) \right|\]
03
Simplify the Calculation
Simplify the above equation for the final area of the triangle:\[Area = \frac{1}{2} \left| 1 \times 3 - 1 \times (-3) + 0 \times 0 \right|\]\[Area = \frac{1}{2} \left| 3 + 3 \right|\]\[Area = \frac{1}{2} \times 6\]
04
Compute the Area of the Triangle
Finally, multiply the value inside the absolute value by \(\frac{1}{2}\):\[Area = 3\]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Coordinate Geometry
Coordinate geometry, also known as analytic geometry, is a branch of mathematics that uses algebraic techniques to solve geometric problems. This field connects geometry and algebra by using coordinate systems. A coordinate system places geometric figures into a numerical framework, allowing us to calculate distances and areas.
- The Cartesian coordinate system is the most common, where every point in space is defined by its coordinates, denoted as \(x, y\) in two dimensions.
- This system allows you to easily identify and work with the properties of geometric figures, such as lines, angles, and polygons.
- Coordinate geometry is particularly useful in calculating the area of irregular shapes, like triangles with vertices having specific coordinate points.
Area Formula
The area formula in coordinate geometry is a handy tool especially for triangles when you are given their vertices. To find the area of a triangle using its vertex coordinates, you apply a specific formula. This formula uses the coordinates \(x_1, y_1\), \(x_2, y_2\), and \(x_3, y_3\).
The formula is expressed as:
\[Area = \frac{1}{2} \left| x_1(y_2-y_3) + x_2(y_3-y_1) + x_3(y_1-y_2) \right|\]This formula efficiently calculates the area by breaking it down into operations that involve the differences in the y-coordinates of the vertices multiplied by the corresponding x-coordinates.
The formula is expressed as:
\[Area = \frac{1}{2} \left| x_1(y_2-y_3) + x_2(y_3-y_1) + x_3(y_1-y_2) \right|\]This formula efficiently calculates the area by breaking it down into operations that involve the differences in the y-coordinates of the vertices multiplied by the corresponding x-coordinates.
- The terms in the formula cover all possible such combinations, ensuring an accurate result.
- The absolute value ensures the area remains a positive number, as area cannot be negative.
- Finally, multiplying by \(\frac{1}{2}\) adjusts the calculated value to actually represent the area, as per geometrical principles.
Vertices of a Triangle
Vertices are critical in geometric calculations as they define the shape and dimensions of polygons like triangles. A vertex is a point where two or more curves, edges, or lines meet.
In the case of triangles, these vertices are the corner points of the three sides. For a triangle defined in coordinate geometry, you will have three critical points: \(x_1, y_1\), \(x_2, y_2\), and \(x_3, y_3\).
In the case of triangles, these vertices are the corner points of the three sides. For a triangle defined in coordinate geometry, you will have three critical points: \(x_1, y_1\), \(x_2, y_2\), and \(x_3, y_3\).
- Each vertex gives you an \(x\) and \(y\) coordinate, pinning down precisely where that point is on the Cartesian plane.
- The choice of your vertices determines the specific orientation and dimension of your triangle.
- In problems asking for the area, properly identifying and substituting these coordinates into the area formula is important for an accurate solution.