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2 votes
Statements

Reasons

1. ZABC is rt. 2

1. A

Identify the missing parts in the proof.

Given: ZABC is a right angle.

DB bisects ABC.

Prove:mZCBD = 45°

2. DB bisects ABC

2. given

3. def. of rt. 2

3. B

A:

4. m ABD = mZCBD

4. def. of bis.

B:

C:

D:

5.C

5. M_ABD + m2CBD = 90°

6. m2CBD + m2CBD = 90°

7. D

6. subs. prop.

7. add.

8. div. prop.

8. mZCBD = 45°

User Amit Kohli
by
7.5k points

2 Answers

1 vote

The missing parts in the proof include the following:

A: Given

B: m∠ABC = 90°

C: Angle Addition Postulate

D: 2m∠CBD = 90°

In Mathematics and Euclidean Geometry, a right angle is a type of angle that is formed in a triangle by the intersection of two (2) straight lines at 90 degrees.

A two-column proof to prove that the measure of angle CBD is 45 degrees should be completed as follows;

Statements Reasons_________________

1. ∠ABC is a right angle 1. Given

2. DB bisects ∠ABC. 2. Given

3. m∠ABC = 90° 3. Definition of right angle.

4. m∠ABD = m∠CBD 4. Definition of bisector

5. m∠ABD + m∠CBD = 90° 5. Angle Addition Postulate.

6. m∠CBD + m∠CBD = 90° 6. Substitution property

7. 2m∠CBD = 90° 7. Addition property

8. m∠CBD = 45° 8. Division property

Missing information:

Identify the missing parts in the proof.

Statements Reasons 1. ZABC is rt. 2 1. A Identify the missing parts in the proof. Given-example-1
User Dellre
by
8.1k points
1 vote

Answer:

See Explanation

Explanation:

The question has unclear information.

So, I'll answer from scratch

Given

ABC = Right angled triangle

DB bisects ABC

Required

Prove that CBD = 45

From the question, we have that:

ABC is right angled at B

So, when DB bisects ABC, it means that DB divides ABC into two equal angles.

i.e.


CBD = ABD

and


CBD + ABD = 90

Substitute CBD for ABD in
CBD + ABD = 90


CBD + CBD = 90


2CBD = 90

Divide both sides by 2


(2CBD)/(2) = (90)/(2)


CBD = (90)/(2)


CBD = 45

Hence, it is proved that
CBD = 45

Follow the above explanation and use it to answer your question properly

User Electrikmilk
by
8.4k points

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