SAT Formulas Sum of the First n Positive Integers: n(n+1)/2 Sum of the First n Odd Integers: n^2 Sum of the First n Even Integers: n(n+1) Angle Sum of a Triangle: 180 degrees Special Right Triangles: 45-45-90: In a 45-45-90 right triangle, the hypotenuse is √2 times the length of each leg. 30-60-90: In a 30-60-90 right triangle, the hypotenuse is twice the length of the shorter leg, and the longer leg is √3 times the length of the shorter leg. Distance, Rate, and Time: d = rt Midpoint Formula: ((x1 + x2)/2, (y1 + y2)/2) Slope Formula: m = (y2 - y1) / (x2 - x1) Quadratic Formula: x = (-b ± √(b^2 - 4ac)) / 2a Perimeter and Area of a Rectangle: Perimeter = 2(length + width), Area = length x width Volume and Surface Area of a Sphere: Volume = (4/3)πr^3 Surface Area = 4πr^2 Volume and Surface Area of a Cone: Volume = (1/3)πr^2h Surface Area = πr^2 + πr√(r^2 + h^2) Volume and Surface Area of a Cylinder: Volume = πr^2h Surface Area = 2πr^2 + 2πrh Distance Formula: d = √((x2 - x1)^2 + (y2 - y1)^2) Law of Sines: (a/sin(A)) = (b/sin(B)) = (c/sin(C)) Law of Cosines: c^2 = a^2 + b^2 - 2ab cos(C)