Explain how the sum and difference formula cos(a+/- b) = cosa cosb -/+ sina sinb could be useful?

The actual width ( w) of a regulation soccer field is 90 meters (m), and the actual length is 120 meters (m). a coach has drawn a scale model of the field on a blackboard. if the longest side of his drawing is 18 cm, how long is the other side of the drawing( w)?

Guys i really need or i have to stay late up night

Hey am have account in but wished to create an account here you guys will me with my make new friends of uk !