Attempt following question by selecting a choice to answer.
c
Lines
AB and
CD intersect at point O. Which of the following statements
is/are always correct?
1.
∠AOC ≅ ∠DOB2.
m∠COB = m∠AOD3.
m∠AOD + m∠AOC = 180oBB ccA.
c1 only
B.
c2 only
C.
c1, 2 and 3
D.
c2 and 3 only
c
C
Step 1: ∠AOC and ∠DOB are congruent.[Vertically opposite angles are congruent.]
Step 2: m∠COB = m∠AOD[Vertically opposite angles are congruent.]
Step 3: The angles ∠AOD and ∠AOC are linear pair of angles.
Step 4: So, sum of their measures is 180o.
Step 5: So, all the three statements are correct.