SAT Right Triangles and Trigonometry Questions
Pythagoras, special right triangles, and sine, cosine and tangent.
In short
- Right Triangles and Trigonometry is part of Geometry and Trigonometry, about 15% of the scored Math questions: 5 to 7 on every test.
- Math questions from all four areas are mixed in each module and arranged from easiest to hardest.
- sin vs. cos side choice is the trap Rivie's practice tests set most often in Right Triangles and Trigonometry questions.
Common traps
Most common first, from Rivie's ten practice tests.
sin vs. cos side choice
In a right triangle, sin(angle) = opposite/hypotenuse, cos(angle) = adjacent/hypotenuse. The wrong choice swaps which side is opposite versus adjacent relative to the angle in question.
The usual mistake: You apply SOH-CAH-TOA to the wrong angle, or flip opposite and adjacent because you didn't physically locate the angle on the figure first.
30-60-90 ratio
30-60-90 triangles have side ratios 1 : √3 : 2 opposite the 30°, 60°, 90° angles respectively. The wrong choice maps a side to the wrong angle.
The usual mistake: You memorize the ratio numbers but lose track of which side corresponds to which angle, putting √3 on the short leg or 1 on the hypotenuse.
Try a question
From Rivie's practice tests. Pick an answer to see why it is right or wrong.
In right triangle ABC with right angle at B, AB = 8 and BC = 6. What is cos A?
Video lessons
Free on YouTube, picked for this topic.