How do you measure angles without a protractor?

Answer 1

Guess <------ O_O

OK well I gonna improve that answer I read it up on the internet that if you measure the angle with a ruler (top to bottom) and multiple it by 20 then you get your answer remember that you can estimate if you don't have to be at the approximate angle

Like 2 can be estimated from 1 3/4

HOPE THIS HELP :)

I really didn't get it

but thanks for trying