Step: Finding the complementary angle
We know that, two angles are said to be complementary when their sum is 90∘
Let complimentary angle of 16 of 90∘ be x∘
∴x∘+16 of 90∘=90∘
⇒x∘+16×90∘=90∘
[BODMAS rule]
⇒x∘+15∘=90∘
∴x∘=75∘
Hence, complementary angle of 16 of 90∘ is 75∘