PLEASE HELP AS FAST AS POSSIBLE

If f(x) and g(x) are inverse functions of each other, which of the following shows the graph of f(g(x)

What does independent variable and dependent variable mean in math?

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