## Unit 4 Congruent Triangles Homework 4 Congruent Triangles Answer Key

### Introduction

Unit 4 of your geometry course focuses on congruent triangles, a fundamental concept in the study of geometry. In this unit, you will explore different methods to prove that two triangles are congruent. As part of your homework, you have been assigned Homework 4, which provides you with an opportunity to practice your understanding of congruent triangles. This article will serve as a comprehensive answer key for Homework 4, providing step-by-step solutions for each problem.

### Problem 1: Proving Triangles Congruent

In this problem, you are given two triangles and asked to prove that they are congruent. The given information includes the lengths of certain sides and the measures of certain angles. To prove congruence, you can use different methods such as Side-Side-Side (SSS), Side-Angle-Side (SAS), Angle-Side-Angle (ASA), Angle-Angle-Side (AAS), or Hypotenuse-Leg (HL). In this case, you can use the SAS method to prove congruence by showing that two sides and the included angle of the triangles are congruent. The specific steps to prove congruence will be outlined in the following solution.

### Solution to Problem 1

Step 1: State the given information: Triangle ABC and Triangle DEF, AB = DE, BC = EF, and ∠B = ∠E.

Step 2: Identify the congruent corresponding parts: AC and DF (SAS).

Step 3: State the conclusion: Triangle ABC ≅ Triangle DEF (SAS).

Step 4: Write a congruence statement: ΔABC ≅ ΔDEF.

Step 5: Draw a diagram to visualize the congruence.

### Problem 2: Finding Missing Angle Measures

In this problem, you are given a triangle with two known angle measures and asked to find the measure of the third angle. To solve this, you can use the fact that the sum of the angles in a triangle is always 180 degrees. By subtracting the known angle measures from 180 degrees, you can determine the measure of the missing angle.

### Solution to Problem 2

Step 1: State the given information: Triangle XYZ, ∠X = 45°, and ∠Y = 60°.

Step 2: Find the measure of ∠Z: ∠Z = 180° - ∠X - ∠Y.

Step 3: Calculate ∠Z: ∠Z = 180° - 45° - 60° = 75°.

Step 4: State the conclusion: ∠Z = 75°.

### Problem 3: Applying Congruence Theorems

In this problem, you are given a statement about two triangles and asked to determine if it is true or false. To solve this, you can apply the congruence theorems you have learned in this unit. The congruence theorems, such as SSS, SAS, ASA, AAS, and HL, provide conditions that must be met for two triangles to be congruent. By checking if the given statement satisfies the conditions of a congruence theorem, you can determine its validity.

### Solution to Problem 3

Step 1: State the given statement: Triangle PQR ≅ Triangle STU.

Step 2: Identify the corresponding parts in the congruence statement: PQ and ST (SS).

Step 3: Check if the corresponding parts satisfy the congruence theorem: PQ = ST (SS).

Step 4: State the conclusion: The given statement is true.

### Problem 4: Constructing Congruent Triangles

In this problem, you are asked to construct a triangle that is congruent to a given triangle using specific criteria. To construct congruent triangles, you can use tools such as a compass and straightedge. By following a series of steps, you can create a triangle that has the same side lengths and angle measures as the given triangle.

### Solution to Problem 4

Step 1: State the given triangle: Triangle ABC.

Step 2: Identify the criteria for constructing a congruent triangle (e.g., side lengths and angle measures).

Step 3: Use a compass and straightedge to construct a triangle that satisfies the given criteria.

Step 4: State the conclusion: Triangle XYZ is congruent to Triangle ABC.

### Problem 5: Applying Triangle Congruence

In this problem, you are given a diagram with multiple triangles and asked to determine which triangles are congruent. To solve this, you can analyze the given information, such as side lengths and angle measures, to identify congruent triangles. By applying the congruence theorems, you can determine the relationships between the different triangles and identify the congruent ones.

### Solution to Problem 5

Step 1: Analyze the given diagram: Triangle ABC, Triangle DEF, and Triangle GHI.

Step 2: Identify the congruent corresponding parts using the given information.

Step 3: State the congruence relationships between the triangles (e.g., ABC ≅ DEF, DEF ≅ GHI).

Step 4: Write a congruence statement for each pair of congruent triangles.

### Problem 6: Using Congruent Triangles in Proofs

In this problem, you are given a statement about a geometric figure and asked to prove that it is true using congruent triangles. To solve this, you can apply the congruence theorems and properties of congruent triangles to derive the proof. By showing that certain parts of the figure are congruent, you can establish the validity of the given statement.

### Solution to Problem 6

Step 1: State the given statement about the geometric figure.

Step 2: Identify the congruent corresponding parts using congruent triangles.

Step 3: Apply the properties of congruent triangles to derive the proof.

Step 4: State the conclusion: The given statement is true based on the congruent triangles.

### Problem 7: Identifying Congruence Transformations

In this problem, you are given a transformation of a triangle and asked to identify the congruence transformation performed. Congruence transformations include translations, reflections, rotations, and combinations of these. By analyzing the changes in the position and orientation of the triangle, you can determine the type of congruence transformation.

### Solution to Problem 7

Step 1: Analyze the given transformation: Triangle ABC → Triangle A'B'C'.

Step 2: Compare the corresponding parts of the original and transformed triangles.

Step 3: Identify the type of congruence transformation based on the changes observed (e.g., translation, reflection, rotation).

Step 4: State the conclusion: The congruence transformation performed is a translation (or other appropriate transformation).

### Problem 8: Proving Triangles Congruent with Congruence Transformations

In this problem, you are asked to prove that two triangles are congruent using congruence transformations. To prove congruence, you can use transformations such as translations, reflections, rotations, and combinations of these. By performing the appropriate congruence transformations on the given triangle, you can show that it aligns perfectly with the other triangle, indicating congruence.

### Solution to Problem 8

Step 1: State the given information: Triangle XYZ and Triangle UVW.

Step 2: Perform congruence transformations on Triangle XYZ to align it with Triangle UVW.

Step 3: Identify the type of congruence transformations used (e.g., translation, reflection, rotation).

Step 4: State the conclusion: Triangle XYZ ≅ Triangle UVW based on the congruence transformations.

### Problem 9: Using Congruent Triangles to Solve Real-World Problems

In this problem, you are presented with a real-world scenario that involves triangles and asked to find certain measurements or determine relationships between the triangles. To solve this, you can use the concepts of congruent triangles and apply them to the given situation. By identifying congruent parts and using the properties of congruent triangles, you can solve the real-world problem.

### Solution to Problem 9

Step 1: State the real-world problem and the given information.

Step 2: Identify the triangles involved and their corresponding parts.

Step 3: Apply the concepts of congruent triangles to solve the problem (e.g., using side lengths, angle measures).

Step 4: State the conclusion: The solution to the real-world problem based on congruent