# GRE MATH FACTS

## 28 terms · Math facts for the GRE

x²-y²

x²+2xy+y²

x²-2xy+y²

(x+y)(x+y)

(x+y)(x-y)

180°

m

a²+b²=c²

ab=k(constant)

### #1 What is the relationship between lengths of the sides of a triangle and the measure of the angles of the triangle?

• The longest side is opposite the largest angle.

### #2 What is the relationship between lengths of the sides of a triangle and the measure of the angles of the triangle?

• The shortest side is opposite the smallest angle.

### #3 What is the relationship between lengths of the sides of a triangle and the measure of the angles of the triangle?

• Sides with the same lengths are opposite angles with the same measure.

y/x is constant

### What is a percent?

A percent is a fraction whose denominator is 100.

### #1 What is an important property of a 30-60-90 triangle?

• The triangle is a right triangle.

### #2 What is an important property of a 30-60-90 triangle?

• The hypotenuse is twice the length of the shorter leg.

### #3 What is an important property of a 30-60-90 triangle?

• The ratio of the length of the three sides is x:x√3:2x

1/xⁿ

A=½bh

V=l×w×h

V=e³

### #1 What are the important properties of a 45-45-90 triangle?

• The triangle is a right triangle.

### #2 What are the important properties of a 45-45-90 triangle?

• The triangle is isosceles (AC=BC).

### #3 What are the important properties of a 45-45-90 triangle?

• The ratio of the lengths of the three sides is x:x:x√2.

### formula for population density

density=population/area

A=6e³

V=πr²h

### formula for distance problems

distance=rate×time or d=rt