GRE Equations

Question 1

Perimeter of a basic triangle

Answer 1

Perimeter = Side 1 + Side 2 + Side 3

Question 2

Area of a basic triangle

Answer 2

Area = 1/2 (Base • Height)

Question 3

Perimeter of equilateral triangle (all sides are equal and all angles are 60°)

Answer 3

Perimeter = 3x

x = any of the equal sides of the triangle

Question 4

Area of an equilateral triangle (all sides are equal and all angles are 60°)

Answer 4

Area = (x^2 • square root of 3) / 4

x = any of the equal sides of the triangle

Question 5

Pythagorean Theorem (Only for right triangles, which always have a 90° angle in the shape)

Answer 5

a^2 + b^2 = c ^2

Question 6

Central Angle Equation

Answer 6

Arc/Circumference = Central Angle/360° = Sector/Area

Question 7

Area of a Circle

Answer 7

Area = Pi • radius squared

Question 8

Circumference of a Circle

Answer 8

Circumference = 2 • Pi • radius = Pi • diameter

Question 9

Perimeter of a Square

Answer 9

Perimeter = 4 • side length

Question 10

Area of a Square

Answer 10

Area = side length squared