Question

: Mark all of the pairs of angles that are complementary. A m∠A=35° and m∠B=65° m ∠ A = 35 ° and m ∠ B = 65 ° B m∠A=21° and m∠B=69° m ∠ A = 21 ° ​ and m ∠ B = 69 ° ​ C m∠A=42° and m∠B=38° m ∠ A = 42 ° ​ and m ∠ B = 38 ° ​ D m∠A=45° and m∠B=45° m ∠ A = 45 ° and m ∠ B = 45 ° ​

Answer 1

(B) m∠A=21° and m∠B=69°

(D) m∠A=45° and m∠B=45°

Explanation:

Two angles are complementary if they sum up to 90 degrees.

(A) m∠A=35° and m∠B=65°

m∠A+m∠B=35°+65°=100°

(B) m∠A=21° and m∠B=69°

m∠A+m∠B=21°+69°=90°

(C) m∠A=42° and m∠B=38°

m∠A+m∠B=42°+38°=80°

(D) m∠A=45° and m∠B=45°

m∠A+m∠B=45°+45°=90°

We can see that only Options B and D gives a result of 90 degrees,

Therefore, the pairs in Options B and D are Complementary.