Solving for Sin with no calculator

1. Sep 4, 2014

BeautifulLight

Solving for Sin with no calculator + additional questions

Sinθ=opp/hyp

Sinθ=5/3

Sinθ=1.6

I know the answer is 35.87°. I would like to convert 1.6 to 35.87° but am unsure how.

Last edited: Sep 4, 2014
2. Sep 4, 2014

mathman

Sinθ=3/5=0.6. You need a calculator or sine table.

3. Sep 4, 2014

BeautifulLight

Oops!

It's impossible to figure out? I am trying to prepare myself for the Accuplacer exam. Calculators are not allowed.

4. Sep 4, 2014

Staff: Mentor

This is not an angle that any reasonable person would expect you to know the sine, cosine, or other trig functions for. So finding that angle means that you'll need to use something to get an approximation; i.e., a calculator or table of trig functions.

A more serious problem is that you misused the formula and calculated hyp/opp, instead of opp/hyp. Also, getting a value larger than 1 for the sine of an angle should have been a red flag. The values of sine and cosine are always between -1 and +1 for real number angles.

5. Sep 4, 2014

Doug Huffman

It's a 3-4-5 triangle. Might someone have suggested memorization of its Pythagorean Triple angles, similar to memorizing the unit circle functions?

6. Sep 4, 2014

Staff: Mentor

Not that I've seen in numerous precalc/trig textbooks. The usual angles to be memorized are 0°, 30°, 45°, 60°, and 90°, along with their counterparts in the other three quadrants.