please answer step by step using correct calculations so I understand how you completed this problem. Thank you​

Indicate the formula for the following conditions: p^c(n,r)=

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

Write the standard form of an equation with (see picture below)