Question

How is sin 10° = cos 80°??​

Answer 1

Check the picture below.

Answer 2

Answer:

See below.

Step-by-step explanation:

Location is Q1

Angle is less than 90

cos Ф = sin(90° - Ф)

cos 80° = sin (90° - 80°)

cos 80° = sin 10°                set your calculator in degree mode

Check

cos 80° = 0.1736481777

sin 10° =  0.1736481777