Formulas
Perimeter
2(L+W) or 2L+2W
A right triangle is half of a what?
Square or rectangle
True or False
The answer to a perimeter problem will be squared
FALSE
Square AREA, not perimeter/circumference
What does 𝝅 equal?
3.14
To create, or break down into individual shapes from one large shape
Decompose
Area of a Square/Rectangle
LxW (or BxH)
Find the area with a base of 10cm and height of 4cm.
10x4=40
40/2=20cm2
What is the area of a rectangle with a length of 12ft, and a width of 3ft?
12x3 = 36ft
What is the radius of a circle with the diameter of 25cm?
12.5cm
Distance from one side of a circle to the other that goes through the center
Diameter
Area of a Circle
A=𝝅r2
What is the area of a triangle if it is half of a square and one side is 8ft?
8x8=64
64/2=32ft2
Find the perimeter of a square that measures 6in wide.
6+6+6+6
or 2(6)+2(6) = 24in
How would you find the circumference of a circle with a radius of 4?
r=4, therefore, d=8
C= 𝝅d =3.14x8
A figure made up of two or more figures
Composite Figure
Area of a Triangle
1/2bh (or bh/2)
Jack's dog run is half of the rectangle patio that is 14ftx10ft, in the shape of a triangle. What is the area of his dog run?
14x10=140
140/2=70ft2
Find the area of a rectangle with a length of 15cm and width of 10cm.
15x10=150cm2
What is the area of a circle with a radius of 3km?
A=3.14(32)
A=3.14(9)
A=28.26km2
The distance around a circle. Pi multiplied by diameter.
Circumference
Circumference of a Circle
C=𝝅d
What is the base of a triangle with a height of 3 and a total area of 9?
9=3b / 2
9x2=3b
18=3b
6=b
Find the total area of a composite figure (in inches) with a rectangle 25 x 5, a square 5x5, and a second rectangle 5x4.
R 25x5=125
S 5x5=25
T 5x4=20
125+25+20=170in2
Find the area of a circle with the diameter of 10in.
A=𝝅r2
A=3.14(52)
A=3.14(5x5)
A=3.14(25)
A=78.5in2
Distance from the center of a circle to any point on the circle
Radius