Distance Between Two Points
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Interactive Audio Lesson
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Introducing the Distance Formula
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Today, we are going to learn about the distance formula. This formula helps us calculate the distance between two points in the Cartesian plane. Can anyone tell me what that formula is?
Is it d equals the square root of the sum of differences?
Close! The formula is actually: $$d = \sqrt{(𝑥_2 - 𝑥_1)^2 + (𝑦_2 - 𝑦_1)^2}$$. Here, (𝑥_1, 𝑦_1) and (𝑥_2, 𝑦_2) are the coordinates of the two points. This is derived from the Pythagorean theorem.
Why is it derived from the Pythagorean theorem?
That's an excellent question! The distance between two points can be thought of as the hypotenuse of a right-angled triangle formed by the differences in their x and y coordinates.
Calculating an Example
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Let’s calculate the distance between points A(2, 3) and B(6, 7). Who can give me the step-by-step process using the distance formula?
First, we subtract the x-coordinates: 6 minus 2 equals 4.
Then we subtract the y-coordinates: 7 minus 3 equals 4 as well.
Exactly! Now, what do we do next?
We square the results, so 4 squared is 16 for both.
Great! What’s the next step?
We add those squares together: 16 plus 16 equals 32.
Correct! Finally, how do we find the distance?
We take the square root of 32, which is 4√2!
Fantastic! You've just calculated the distance using the formula.
Introduction & Overview
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Quick Overview
Standard
In this section, we explore how to calculate the distance between two points on a Cartesian plane using the distance formula. We also examine a practical example to reinforce understanding.
Detailed
Detailed Summary
The distance between two points in a Cartesian coordinate system is calculated using the distance formula, which is derived from the Pythagorean theorem. Given two points, A (𝑥_1,𝑦_1) and B(𝑥_2,𝑦_2), the formula to find the distance (d) is:
$$
d = \sqrt{(𝑥_2 - 𝑥_1)^2 + (𝑦_2 - 𝑦_1)^2}
$$
This formula allows us to determine how far apart two points are on a two-dimensional plane. For instance, if we want to find the distance between points A(2, 3) and B(6, 7), substituting these values into the formula provides us with a result of 4√2. Understanding this concept is essential as it forms the basis for further geometric analysis, such as finding midpoints and analyzing the slopes and equations of lines.
Audio Book
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Distance Formula
Chapter 1 of 2
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Chapter Content
The distance 𝑑 between two points 𝐴(𝑥₁,𝑦₁) and 𝐵(𝑥₂,𝑦₂) is given by:
𝑑 = √((𝑥₂ − 𝑥₁)² + (𝑦₂ − 𝑦₁)²)
Detailed Explanation
The distance formula calculates the straight-line distance between two points on a Cartesian coordinate plane. The formula is derived from the Pythagorean theorem, which relates the lengths of the sides of a right triangle. In this case, if you imagine a right triangle formed by the two points 𝐴 and 𝐵, the difference in their x-coordinates (𝑥₂ − 𝑥₁) gives you the length of one side, and the difference in their y-coordinates (𝑦₂ − 𝑦₁) gives you the length of the other side. By squaring these lengths and adding them together, you can find the square of the hypotenuse (the distance between the points). Finally, taking the square root gives you the actual distance.
Examples & Analogies
Think of finding a route between two locations on a map. The formula is like using a ruler to measure the shortest path between two points on that map, without having to account for any detours or turns you might take along a winding road.
Example Calculation
Chapter 2 of 2
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Chapter Content
📌 Example:
Find the distance between 𝐴(2,3) and 𝐵(6,7):
𝑑 = √((6−2)² + (7−3)²) = √(16 + 16) = √32 = 4√2
Detailed Explanation
In this example, we calculate the distance between points 𝐴(2,3) and 𝐵(6,7). First, we substitute the coordinates into the distance formula. The x-coordinates yield (6 - 2)², which equals 4² = 16, and the y-coordinates yield (7 - 3)², which also equals 4² = 16. Thus, we add these results together, giving us √(16 + 16) = √32. Since √32 can be simplified to 4√2, we conclude that the distance is approximately 5.66 units.
Examples & Analogies
Imagine measuring the distance between two points in a park. If point 𝐴 is at coordinates (2,3) and point 𝐵 is at (6,7), you're basically determining how far apart two picnic spots are, as if you were walking the straight line connecting both spots.
Key Concepts
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Distance Formula: Determines the distance between two points in a 2D plane using the coordinates of those points.
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Pythagorean Theorem: A principle used to derive the distance formula, stating that in a right triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.
Examples & Applications
To find the distance between points A(2, 3) and B(6, 7), use the distance formula to calculate a distance of 4√2.
The distance between points C(1, 1) and D(4, 5) calculates to √((4-1)² + (5-1)²) = √(9 + 16) = √25 = 5.
Memory Aids
Interactive tools to help you remember key concepts
Rhymes
To find the distance, here’s the rule,
Stories
Imagine two friends walking in a park, connecting points on a grid. To find the shortest path between them, they use a special recipe known as the distance formula, ensuring they won’t walk too far.
Memory Tools
To remember the distance formula: 'x2-x1, y2-y1, square it, sum it, take a root, and you’re done!'
Acronyms
D = Square the differences to calculate (D = SD²), where SD is the side difference.
Flash Cards
Glossary
- Distance Formula
A mathematical equation used to determine the distance between two points in a Cartesian plane.
- Cartesian Plane
A two-dimensional coordinate system defined by a horizontal axis (x-axis) and a vertical axis (y-axis).
- Hypotenuse
The longest side of a right triangle, opposite the right angle.
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