If two variables, a and b, are proportional, which of the following expressions must be constant?

What is the smallest integer n such that n\sqrt{2} is greater than 20

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

The functions f(x) and g(x) are shown in the graph f(x)=x^2 what is g(x) ?