Answer:
The missing parts of the proof includes;
1) ∠ABC = m∠CBD + m∠ABD = 90° (Angle addition postulate)
2) m∠CBD = m∠ABD (Definition of angle bisector)
3) m∠CBD + m∠ABD = m∠CBD + m∠CBD (Substitution property of equality)
Step-by-step explanation:
The given details of the proof are;
∠ABC is a right angle = 90°
Line DB is a bisector of ∠ABC
Therefore;
1) ∠ABC = m∠CBD + m∠ABD = 90° by angle addition postulate
By the definition of angle bisector, we have;
The angles formed by line DB from ∠ABC are equal,
2) m∠CBD = m∠ABD by the definition of angle bisector
3) m∠CBD + m∠ABD = 90° = m∠CBD + m∠CBD = 2 × m∠CBD by substitution property of equality
2 × m∠CBD = 90°
∴ m∠CBD = 90°/2 = 45°
Answer:
A: Given
B: measure the angle ABC = 90
C: angle addition postulate
D: 2 times the measure of angle CBD = 90
Step-by-step explanation:
Hope this helps <3
