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1.

Given: ΔABC is a right triangle
∠A is a right angle
m∠B = 45˚
Prove: ∠B ≅ ∠C
STATEMENT: REASON:


2.
Given: m∠X = 4a + 2
m∠Y = 21a + 3
∠X and ∠Y are a linear pair
Prove: ∠Y is an obtuse angle
STATEMENT: REASON:

3.
Given: ∠A and ∠B are complementary angles
∠B and ∠C are complementary angles
Prove: ∠A ≅ ∠C
STATEMENT: REASON:

4.
Given: ΔMNP is a right triangle
∠M is a right angle
Prove: ∠N and ∠P are complementary angles
STATEMENT: REASON:

1 Answer

6 votes

Final answer:

The students' questions are addressed using geometric principles such as the Triangle Sum Theorem and the Linear Pair Postulate, demonstrating how to prove angle congruences and relationships in triangles.

Step-by-step explanation:

To address the geometry problems presented by the student, we shall use fundamental geometric principles and theorems.

1. Proving ∠B ≅ ∠C in a right triangle with one 45° angle

Triangle Sum Theorem: The sum of angles in a triangle is 180°.

In ΔABC, m∠A + m∠B + m∠C = 180°.

Since ∠A is a right angle, m∠A = 90° and we are given m∠B = 45°.

So, m∠C = 180° - 90° - 45° = 45°. Therefore, ∠B ≅ ∠C.

2. Proving ∠Y is an obtuse angle

Linear Pair Postulate: Angles forming a linear pair sum to 180°.

m∠X + m∠Y = 180° because ∠X and ∠Y are a linear pair.

Substitute the given expressions: (4a + 2) + (21a + 3) = 180°.

Solve for a, then calculate m∠Y. If m∠Y > 90°, then ∠Y is obtuse.

3. Proving ∠A and ∠C are equal

Complementary Angles: Two angles are complementary if their measures sum to 90°.

Since ∠A and ∠B are complementary: m∠A + m∠B = 90°.

Since ∠B and ∠C are also complementary: m∠B + m∠C = 90°.

Therefore, m∠A must equal m∠C, which means ∠A ≅ ∠C.

4. Proving ∠N and ∠P are complementary angles in ΔMNP

Triangle Sum Theorem: The sum of angles in a triangle is 180°.

In ΔMNP, m∠M + m∠N + m∠P = 180°.

Since ∠M is a right angle, m∠M = 90°.

Thus, m∠N + m∠P = 90°, indicating ∠N and ∠P are complementary.

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