Grade 8 Math ChartBy: Brandon Wright

Perimeter

The distance around a 2 dimensional shape

Square P= 4s

Rectangle P= 2l+2w or P= 2 (l + w)

What is the perimeter of this rectangle?

8 in.

2 in.

Answer- 20 in.

What is the perimeter of this square?

4 in.

4 in.

Answer- 16 in.

Circumference

The perimeter of a circle

Circle C= 2πr or C= πd

What is the circumference of a circle if the diameter is14 cm.?

Answer- 42 cm.

AreaThe area is the surface of an object

measured in squared units

Square A= s2

Rectangle A= lw or A= bh

Triangle A= 1/2 bh or A= bh/2

Area Continued

Trapezoid A= 1/2 (b1 + b2) or A=(b1+b2)h/2

Circle A= πr2

What is the area of this square?

7 in.

7 in.

Answer- 49 in2

What is the area of this rectangle?

8 cm.

5cm.

Answer- 40 cm2

What is the area of this triangle?

9 in.

4 in. Answer- 18 in2

What is the area of this trapezoid if the height is 9 cm.?

11 cm.

15 cm. Answer- 117 cm2

What is the area of a circle if the radius is 12 cm.?

Answer- 452 cm2

P represents the perimeter of the base of a three dimensional figure.

B is the area of the base of a three dimensional figure.

Surface Area

The extent of a 2D surface enclosed in a boundary

Cube 6s2

Prism (Lateral) Ph

Prism (Total) Ph + 2B

Pyramid (Lateral) 1/2 PL

Surface Area Cont.

Pyramid (Total) ½ Pl + B

Cylinder (Lateral) 2πrh

Cylinder (Total) 2πr(h + r)

What’s the surface area of this cube if one side is 8 in. long?

8 in.

Answer- 384 in.

What is the surface area of this lateral prism if the height is 5 cm. and the perimeter of the base is 10 cm.?

Answer- 50 cm.

What is the surface area of this total prism if the perimeter of the base is 10 cm. the area is 16 cm. and the height is 18 cm.?

Answer- 212 cm.

What is the surface area of this lateral prism if the base’s perimeter is 10 in. and the length is 8 in.?

Answer- 40 in.

What’s the surface area of a total pyramid if the area of the base is 16 in. the perimeter is 16 in. and the length is 8 in.?

Answer- 72 in.

What’s the surface area of a lateral cylinder if the radius is 8 cm. and the height is 10 cm.?

Answer- 240 cm.

What is the surface area of a total cylinder if the height is 10 in. and the radius is14 in.?

Answer- 2016 in.

Volume

The amount of space an object takes up

Cube S= 6s2

Prism S= Ph

Pyramid S= ½ Pl

Cylinder S= 2πrh

What is the volume of a prism that the base area is 16 in. and the height is 12 in.?

Answer- 192 in3

What is the volume of a cylinder if the area of the base is 36 cm. and the height is 14 cm.?

Answer- 504 cm3

What is the volume of a pyramid if the area of the base is 16 in. and the height is 9 in.?

Answer- 48 in3

What is the volume of a cone if the area of the base is 9 cm. and the height is also 9 cm.?

Answer- 27 cm3

What is the volume of this sphere if the radius is 5 in.?

Answer- 500 in3

Pi

Ratio of a circumference of a circle of its diameter

3.14 or 22/7

What is the area of a circle if the diameter is 6 in. and the formula is πr2?

Answer- 108 in2

Pythagorean Theorem

A theorem that the square of the hypotenuse of a right triangle is equal to the sum of the squares of the other two sides

a2 + b2= c2

If two angles in a triangle are 100o and 35o than what is the measure of the third angle?

Answer- 45o

Simple Interest Formula

When you borrow money and need to pay it back

I= prt

P = $15,000R = 15%T = 3 yearsFind I.

Answer- $6750

Linear Equation

An equation whereby letters represent real numbers and whose graph is a line

4y = 2(x + 2y)

x= 4(3y) – 12

If y is 3, then what is x?

Answer- 24

Function

The idea that one quantity completely determines another quantity

x {2,4,6,8}Find the y values if the function is

x2=y.

y {4,8,12,16}

Function Notation

A notation that describes a function

f(x) = 2x 2 + 3x + 4

Domain

The x point

What is the domain? (8, 6)

Answer- 8

Range

The y point

(8, 6)

Whats the range?

Answer- 6

Ratios

Comparing a number to another number like 3:4, 3 to 4, or 3/4

The ratio of boys to girls is 5:3 so if there is 30 girls how many boys are there? What is the new ratio?

Answer- 18; 30:18