SAT · Additional Topics in Math · Right triangle trigonometry
Question sat-q-00180
Hard Multiple choice No calculator
The question
What is the value of sin(45°)?
- √2/2
- 1
- ½
- √3/2
Show answer & worked solution
Answer: √2/2
Worked solution. Recall the unit circle: sin(45°) = √2/2.
Why each wrong choice is wrong. The classic distractor swaps sine and cosine values for the same angle. Drilling the unit circle eliminates this entirely.
Test-day tactic. Memorize sine and cosine at 0°, 30°, 45°, 60°, and 90°. The values are short and they appear constantly.
About this question type
Items test the basic trig ratios (sine, cosine, tangent), the special right triangles (30-60-90 and 45-45-90), and the Pythagorean theorem. Common surface forms include finding a missing side given an angle and a side, finding an angle given two sides, or recognizing a Pythagorean triple in disguise.
You will see a question shaped like this one on roughly every other official SAT form, typically at the back end of the section, where the score gradient is steepest. Treat any miss in this subtopic as a signal to drill the subtopic page before you do another full practice test.