Answer:
The sum of the measures of two complementary angles is 90 degrees
Explanation:
we know that
If two angles are complementary, then their sum is equal to 90 degrees
In this problem we have that
m∠ABD and m∠DBC are complementary
so
m∠ABD + m∠DBC=90° -----> by complementary angles
and
(m∠ABD + m∠DBC)+m∠EBC=180° -----> by a linear pair
Find the measure of angle EBC
substitute the given values
(90°)+m∠EBC=180°
∠EBC=180°-90°=90°