# Summary of geometry

Last updated: 4 Nov 2008

In this tutorial you have learned all the geometry you need for the GMAT.

All the equations and vocabulary you need are summarized below to make them easy to revise.

### Equations

You must learn the following equations to be able to answer geometry questions successfully. Remember you cannot take notes into the GMAT.

**Area of a Triangle**= \(\frac{1}{2} b h\)**The Pythagoras Theorem**: \(a^{2} + b^{2} = c^{2}\)**Area of a Trapezium**= \(\frac{1}{2} (b_1 + b_2) h\)**Area of a Circle**= \(\pi r^{2}\)**Circumference**= \(2 \pi r\)**Volume of a Cuboid**= \(lwh\)**Surface Area of a Cuboid**= \(2(lh + wh + lw)\)**Volume of a Cylinder**= \(\pi r^{2} h\)**Surface Area of a Cylinder**= \(2 \pi r (r + h)\)**Equation of a Line**: \(y = mx + c\)

### Vocabulary

It is useful to know the following vocabulary.

**Bisect**: Cut exactly in half.**Circumference**: The perimeter of a circle.**Gradient**: The rate at which a line goes up (or down).**Parallel**: Lines which lie in a plane and never meet.**Perimeter**: The length of the border of a shape.**Perpendicular**: At right angles.**Slope**: The rate at which a line goes up (or down). See also 'Gradient'.**Surface Area**: The area of the faces of a shape.**Trisect**: Cut exactly in three.: Point at which a line crosses the y-axis.*y*intersect