## Unit 3 Test Parallel and Perpendicular Lines Answer Key PDF

In this article, we will provide you with the answer key for the Unit 3 Test on parallel and perpendicular lines. We understand that studying for a math test can be challenging, especially when it comes to understanding the properties and relationships of these lines. That's why we have put together this comprehensive answer key in PDF format to help you review and prepare for your upcoming test. So, let's dive right in!

### Introduction

Before we begin with the answer key, let's briefly recap what parallel and perpendicular lines are. Parallel lines are two or more lines that never intersect and are always equidistant from each other. On the other hand, perpendicular lines are two lines that intersect at a right angle, forming 90-degree angles.

### Answer Key

### Question 1: Identify Parallel Lines

The first question on the test asks you to identify the parallel lines from a given set. To solve this question, you need to look for lines that have the same slope. Remember, the slope of parallel lines is always equal. The answer to this question can vary, but here are a few examples:

- Line 1: y = 2x + 3
- Line 2: y = 2x - 1
- Line 3: y = -2x + 5

In this example, Line 1 and Line 2 are parallel because they have the same slope of 2. Line 3 is not parallel to Line 1 or Line 2 because it has a different slope of -2.

### Question 2: Determine Perpendicular Lines

The second question tests your understanding of perpendicular lines. To solve this question, you need to find lines that have slopes that are negative reciprocals of each other. In other words, if one line has a slope of m, the perpendicular line will have a slope of -1/m. Here's an example:

- Line 1: y = 3x + 2
- Line 2: y = -1/3x + 5

In this example, Line 1 and Line 2 are perpendicular because the slope of Line 1 is 3, and the slope of Line 2 is -1/3, which is the negative reciprocal of 3.

### Question 3: Find the Equations of Parallel and Perpendicular Lines

The third question requires you to find the equations of parallel and perpendicular lines based on given information. To solve this question, you can use the point-slope form of the equation, which is y - y1 = m(x - x1). Here's an example:

- Point: (2, 4)
- Parallel Line: y = 2x + 1
- Perpendicular Line: y = -1/2x + 6

To find the equation of the parallel line, we can use the given point (2, 4) and the slope (2) to get y - 4 = 2(x - 2), which simplifies to y - 4 = 2x - 4. Similarly, for the perpendicular line, we can use the given point (2, 4) and the slope (-1/2) to get y - 4 = -1/2(x - 2), which simplifies to y - 4 = -1/2x + 1.

### Question 4: Solve for the Unknown Angle

The fourth question involves solving for an unknown angle formed by parallel or perpendicular lines. To solve this question, you need to know that parallel lines create congruent alternate interior angles, while perpendicular lines create congruent vertical angles. Here's an example:

- Line 1: m∠1 = 45°
- Line 2: m∠2 = ?

In this example, Line 1 and Line 2 are parallel. Therefore, ∠1 and ∠2 are congruent alternate interior angles, meaning that m∠2 is also 45°.

### Question 5: Determine the Distance between Parallel Lines

The fifth question asks you to find the distance between two parallel lines. To solve this question, you can use the formula for the distance between a point and a line. Here's an example:

- Line 1: y = 2x + 3
- Line 2: y = 2x - 1
- Point: (4, 5)

In this example, we want to find the distance between Line 1 and Line 2. We can choose any point on one line, such as (4, 5), and use the formula to calculate the distance. The formula is given by d = |Ax + By + C| / √(A^2 + B^2), where A, B, and C are the coefficients of the line equations. After substituting the values, we can find the distance between the lines.

### Conclusion

Math tests can be challenging, especially when it comes to understanding the properties and relationships of parallel and perpendicular lines. However, with the help of this answer key in PDF format, you can review and prepare for your upcoming test more effectively. We hope that this article has provided you with the necessary guidance and clarity to tackle the Unit 3 Test successfully. Good luck!