Check the picture below.
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
