Triangle Properties
Understand triangle types, similarity, congruence, and special triangles.
Practice Problems
Right triangle: legs 6 and 8
Pro Tips & Shortcuts
SAT Tip: This is the most tested triangle property on the SAT.
SAT Tip: Use this to check if given side lengths can actually form a triangle.
SAT Tip: If you see equal sides marked, the opposite angles are also equal.
SAT Tip: Memorize Pythagorean triples to save time: 3-4-5 and its multiples (6-8-10, 9-12-15, etc.)
SAT Tip: Recognize this as 2 times the 3-4-5 triple to solve instantly.
To find missing angle: subtract the other two from 180°.
Quick check: is the longest side less than the sum of the other two?
Equilateral triangle: all angles are 180°/3 = 60°.
If you see a right triangle, think Pythagorean theorem immediately.
6-8-10 is just 3-4-5 multiplied by 2.