>>16996203
slide rules and trig identities

>>16996203
1. Get a protractor that is divided to show 28 degree
2. draw that unit circle.
3. measure that vertical length labeled sin with a metered ruler divided by the unit circles radius?
Before calculator they either use some good enough approximation or look up in pronted look up table

>>16996203
Lookup tables, physical measurements or good enough approximations depending on use case.

>>16996203
As others mentioned, lookup tables existed. Hell, any textbook that addresses trig functions more than likely has a lookup table somewhere in the index.

Other than that, the test makers would be aware what the students had available to them. They wouldn't ask a question which requires a calculator in a time when calculators didn't exist. If contemporary tools made the problem tedious and take a long time, there'd be fewer questions like that.

>>16996219
are you a wizard?

File: sin28.png (173.5 KB)

>>16996203
sin(28°) ≈ 0.469472

File: sliderule.png (896.1 KB)

>>16996203

>>16996243
In a few years if not left unmarried

>>16996203
Tests can and should be designed in a way that you don't need a calculator