Pre Algebra Big Ideas

Formulas

100

Pythagorean Thrm

a²+b²=c²

200

Simple Interest

I = prt

300

Interoir Angle Sum

S= (n-2)^.180

400

Circle Area

Circle Circumference

A= pi r²

C= 2 pi r

500

y - int form

point slope form

standard form

direct variation

y = mx+b

y₁-y = m(x₁-x)

ax+by=c

y=mx=kx

Exponents and Scientific

100

a^m/aⁿ

a^m-n

200

a^-n

1/aⁿ

300

scientific notation

a ^. 10ⁿ   1<a<10

               ^- 

400

(a^.10^m)(b^.10ⁿ)

ab^.10^m+n

500

(a^.10^m)/(b^.10ⁿ)

(a/b)^. 10^m-n

Reflections and Rotations

100

reflect over x-axis

(x,y)->

reflect over y-axis

(x,y)->

(x,-y)

(-x,y)

200

Reflection over y = x

(x,y) ->

Reflection over y = -x

(x,y) ->

(y,x)

(-y,-x)

300

Rotate 90 degrees clockwise

(x,y) ->

(y, -x)

400

Rotation 180 degrees

(x,y) ->

(-x,-y)

500

Rotate 90 degrees counter-clockwise

(x,y) ->

(-y,x)

Shapes and Inequalities

100

area of rectangle

area of triangle

a = bh

a = ¹/₂bh

200

area of semi-circle

a = ¹/₂pi r²

300

Multiply or devide an inequality by a negative number

FLIP THE SIGN

400

Sphere volume

Cone volume

Cylinder volume

V= ⁴/₃pi r³

V= ¹/₃pi r²h

V = pi r² h

500

pyramid Volume

Triangular prism volume

v =¹/₃Bh

v = Bh=¹/₂bwh

Solve

100

Write 3.42 ^. 10^-4 in standard form.

0.000342.

200

Write 58,000,000 in scientific notation.

5.8 ^. 10⁷

300

Similar solids have a scale factor of 3. What is the volume scale factor?

27

400

Two similar solids have volumes 8 and 216. What is the linear scale factor from smaller to larger.

3

500

two similar figures have areas 24 and 100. what is the linear scale factor from small to large?

^5_/6/₆ = 2.04