Important Geometry Formulas to Know for the ISEE Math Tests

Geometry! Greeks loved it, but most people not so much. However, geometry is everywhere, and furthermore, you need to know geometry as one of the 4 important areas of math if you want to ace the Mathematics Achievement and Quantitative Reasoning tests on the ISEE. Geometry tends to be confusing due to the huge number of formulas and concepts, but at Union Test Prep, we’ve narrowed it down to the essential formulas so you can have them all in a single chart.

Use the chart below and our other three formula charts (linked below) as you prepare for the ISEE test:

For practice and more information, check out our FREE study guides, practice questions, and flashcards for the ISEE.

Geometry Formulas for the ISEE Math Tests

Category Formula Symbols Comment
Two
Dimensional
Shapes
$$\Sigma \theta = (n-2) \cdot 180^\circ$$ $$\Sigma \theta$$ = sum of interior angles
n = number of sides of a polygon

Two
Dimensional
Shapes
$$P=s_1 + s_2 + s_3$$ P = Perimeter of a triangle
$$s_n$$ = side length

Two
Dimensional
Shapes
$$A=\frac{1}{2} \cdot b \cdot h$$ A = area of triangle
b = base
h = height

Two
Dimensional
Shapes
$$a^2+b^2=c^2$$ a, b = legs of a right triangle
c = hypotenuse of a right triangle

Two
Dimensional
Shapes
$$P=4 \cdot s$$ P = Perimeter of a square
s = side length

Two
Dimensional
Shapes
$$P=(2 \cdot l)+(2 \cdot w)$$ P = Perimeter of a rectangle
l = length
w = width

Two
Dimensional
Shapes
$$A=s^2$$ A = Area of a square
s = side length

Two
Dimensional
Shapes
$$A=l \cdot w$$ A = Area of a rectangle
l = length
w = width

Two
Dimensional
Shapes
$$A=h \cdot \frac{(b_1+b_2)}{2}$$ A = Area of a trapezoid
$$b_n$$ = base n
h = height

Two
Dimensional
Shapes
$$C=2 \cdot \pi \cdot r$$ or $$C=\pi \cdot d$$ C = Perimeter of a circle
d = diameter

Two
Dimensional
Shapes
$$S=r \theta$$ s = arc length
$$\theta$$ = central angle (radians)

Two
Dimensional
Shapes
$$A=\pi \cdot r^2$$ A = Area of a circle

Three
Dimensional
Shapes
$$V=l \cdot w \cdot h$$ V = Volume of a rectangular prism
l = length
w = width
h = height

Three
Dimensional
Shapes
$$SA= \Sigma A_{fi}$$ SA = Surface Area of a prism
$$A_{fi}$$ = Area of face i

Three
Dimensional
Shapes
$$V=\frac{1}{3} \cdot (l \cdot w \cdot h)$$ V = Volume of a pyramid with rectangular base
l = length
w = width
h = height

Three
Dimensional
Shapes
$$SA=\Sigma A_{fi}$$ SA = Surface Area of a pyramid
$$A_{fi}$$ = Area of face i

Three
Dimensional
Shapes
$$V= \pi \cdot r^2 \cdot h$$ V = Volume of a cylinder
h = height

Three
Dimensional
Shapes
$$SA=2B+(C \cdot h)$$ SA = Surface Area of a cylinder
B = Area of the Base
C = Circumference of the Base
h = height

Three
Dimensional
Shapes
$$V= \frac{4}{3} \cdot \pi \cdot r^3$$ V = Volume of a sphere
$$SA=4 \cdot \pi \cdot r^2$$ SA = Surface Area of a sphere