Set A = {factors of 72}
set B ={multiples of 3 less than 20}
set C ={prime numbers less than 30}
find i. A n B n C
ii. A n B

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