What is 6/5÷7/1 can u tell me pls

In the diagram of circle o, what is the measure of zabc?

1. ∠1 is complementary to ∠2 and ∠3 is complementary to ∠2. subtraction property of equality 2. m∠1 + m∠2 = 90 and m∠3 + m∠2 = 90 substitution 3. m∠1 + m∠2 = m∠3 + m∠2 definition of complementary 4. m∠1 = m∠3 given

In an isosceles triangle, the vertex angle is 112 degrees. what is the measure of each base. a.34 b.24 c.44 d.54