Mastering dilations on the coordinate plane can significantly enhance your understanding of geometry and transformations. In this guide, we will explore what dilations are, how they work, and provide a worksheet to practice. π
What Are Dilations? π€
Dilations are a type of transformation that alters the size of a figure without changing its shape. They are characterized by a center of dilation and a scale factor. The center of dilation is a fixed point in the plane, and the scale factor determines how much the figure is enlarged or reduced.
Center of Dilation π
- Definition: The fixed point from which all points of the figure are dilated.
- Notation: Often labeled as ( C ).
Scale Factor π’
- Definition: The ratio of the distance from the center of dilation to the image compared to the distance from the center to the pre-image.
- Notation: Denoted as ( k ).
- If ( k > 1 ), the figure is enlarged.
- If ( 0 < k < 1 ), the figure is reduced.
How to Perform Dilations π
To perform a dilation on the coordinate plane, follow these steps:
- Identify the Center of Dilation: Choose a point that will remain fixed.
- Determine the Scale Factor: Decide whether you want to enlarge or reduce the figure.
- Apply the Dilation Formula: For each point ( (x, y) ): [ (x', y') = (k(x - C_x) + C_x, k(y - C_y) + C_y) ] Here, ( (C_x, C_y) ) are the coordinates of the center of dilation.
Example: Performing a Dilation
Letβs say we have a triangle with vertices at ( A(1, 2) ), ( B(3, 4) ), and ( C(5, 2) ). We will dilate this triangle with a center at ( C(0, 0) ) and a scale factor of ( k = 2 ).
- Dilate Point A: [ A' = (2(1 - 0) + 0, 2(2 - 0) + 0) = (2, 4) ]
- Dilate Point B: [ B' = (2(3 - 0) + 0, 2(4 - 0) + 0) = (6, 8) ]
- Dilate Point C: [ C' = (2(5 - 0) + 0, 2(2 - 0) + 0) = (10, 4) ]
The new dilated triangle has vertices at ( A'(2, 4) ), ( B'(6, 8) ), and ( C'(10, 4) ).
Important Notes π
- When using a center of dilation that is not the origin, be careful with your calculations.
- Ensure you understand the concept of ratios, as the scale factor represents a ratio of the distances.
Worksheet: Practice Problems π
Now that you have a grasp of dilations, it's time to put your skills to the test! Below is a worksheet containing practice problems.
Dilation Worksheet Problems
Problem No. | Original Points | Center of Dilation | Scale Factor | Solution Points |
---|---|---|---|---|
1 | ( P(2, 3) ) | ( (0, 0) ) | ( k = 3 ) | |
2 | ( Q(1, -1) ) | ( (1, 1) ) | ( k = 0.5 ) | |
3 | ( R(-2, 2) ) | ( (3, 3) ) | ( k = 1 ) | |
4 | ( S(4, 5) ) | ( (2, 2) ) | ( k = 2 ) | |
5 | ( T(-1, -3) ) | ( (1, 1) ) | ( k = -1 ) |
Instructions: For each problem, apply the dilation formula to find the new points.
Conclusion π
Mastering dilations is a fundamental skill in geometry that lays the groundwork for more complex transformations and understanding of shapes. By practicing with the worksheet provided, you will gain confidence in performing dilations on the coordinate plane. Remember, the key elements are the center of dilation and the scale factor; understanding these will ensure success as you dive deeper into the fascinating world of geometry! Happy learning! βοΈ