This document provides formulas for various concepts in elementary algebra including: 1) Perimeter and area formulas for rectangles, triangles, circles, trapezoids, rhombuses/parallelograms. 2) Surface area and volume formulas for rectangular prisms, cubes, cylinders, cones, spheres, pyramids. 3) Formulas for interest, conversions between units, factoring special products, slope of a line, and equations of lines.

1. FORMULAS IN ELEMENTARY ALGEBRA
A. Perimeter
Rectangle – 2l + 2w
Triangle– a + b + c
Circle- 2πr
B. Area
Rectangle – lw
Triangle– bh
2
1
Circle– πr2
Trapezoid –
2
h)b+b( 21
Rhombus /Parallelogram –
2
bh
C. Surface Area
Rectangular Prism– 2(lw+lh + wh)
Cube – 6s2
Cylinder – 2πr2 + 2πrh
Cone – πr2 + πrs
Sphere – 4πr2
D. Volume
Rectangular Prism– lwh
Cube – s3
Cylinder – πr2h
Cone – hrπ
3
1 2
Sphere –
3
4
πr3
Pyramid – hA
3
1
base
E. Interest
I = Prt, t in years
F. Conversion
1 hectare (ha) = 10, 000 m2
100 hectare (ha) = 1 km2
1 dm3 = 1 L
1 cm3 = 1 mL
0C = ( )32F
9
5
-
0F = 32+C
5
9
G. Special Products / Factoring
a2 – b2 = (a + b)(a – b)
a3 + b3 = (a + b)(a2 – ab + b2)
a3 – b3 = (a – b)(a2 + ab + b2)
ax + ay + bx + by = (x + y)(a + b)
H. Slope of a Line (m) =
12
1
x-x
y-2y
I. Equation of a Line: y = m(x – x1) + y1
j. Equation of a Line Given its Intercepts
01- =
b
y
+
a
x
K. Area of the Region bounded by Line and the Axes :
A = int-int- yx
2
1
L. Distance of Between Two Points
d = 22
2 )y(+)x( 121 y-x-
M. Midpoint of a Segment
M = )
2
y+y
,
2
x+x
(
2121
N. Vertex of y =  ax + b  + c : V(-b/a, c)
O. Range of y =  ax + b  + c : y > c
P. Range of y = -  ax + b  + c : y < c
Q. Maximum/Minimum Value of y =  ax + b  + c
y = c
R. Area of a Triangle Given the Coordinates of the
vertices of the Triangle
A =
2
)yx+yx+y)yx+yx+yx( 23123133221 1(x-
S. Smaller Angle Between Two Hands of a Clock
 =
2
x60 11y-
x – hours y – minutes
LCM x GCF = a x b