All Topics
Geometry
Triangles: Types and Rules
三角形：类型与法则
Low frequency
Exam Frequency
1
avg per test
1
Quantitative Reasoning
0
Math Achievement
What to Study
- Right triangles
- Equilateral triangles
- Isosceles triangles
- Special right triangles (30-60-90, 45-45-90)
- Pythagorean theorem (a² + b² = c²)
- Common Pythagorean triples (3-4-5, 5-12-13, 8-15-17, 7-24-25)
- Similar triangles and ratios
- Area of triangles (A = ½bh)
- Triangle inequality theorem
- Interior angles sum = 180°
Key Formulas
Area = ½ × base × height
Perimeter = a + b + c
a² + b² = c² (right triangle)
Interior angles sum = 180°
30-60-90: sides = x, x√3, 2x
45-45-90: sides = x, x, x√2