Geometry test review notes
How to find the area of a parallelogram
Base times height
Base is a straight line,Height is usually a dotted line
How to find the area of a triangle
Half of the base times height
Multiply 30 (base)*20 (height) then divide by 2
How to find the area of a trapezoid
Base one + base two * height divided by 2
The bases are always the top and bottom
20.5 + 13.5 = 34 *10 is 340/2 is 170
How to find the area of a square or rectangle
Base * height
Or length times width
Circles review
● ***Radius= half of diameter***
● Circumference= 3.14 * the diameter
● Area= 3.14 * diameter (radius * 2)
Ex. What is the circumference of a circle with a radius of 5.2
5.2 * 2 = 10.4
10.4 * 3.14 = 32.656
Example Problems
What is the area of the irregular figure ?
First rectangle
8 * 13 = 104
Put semi circles together to form a circle
The circle has a diameter of 8
Then find the area
3.14 * 4 * 4 = 50.2
NOW ADD
50.24 + 104 = 154.24
Final answer :154.24
How to find the Volume of a triangular prism
Volume = Area of base * height of prism
First find the area of the the triangle
0.5 * 4 * 3 = 6
Then multiply 6 * 6 (which is the height of the triangular prism)
Your final answer is 36 that would be 36cm squared
Surface area
How to find the surface area of a triangular prism
1. Find the area of the triangle face 10*8 divided by 2
That would be 40
Add both faces ( which would have the same area )
40+40=80
2.Find area of the squares 180 + 180 = 360
3.Find the area of the bottom square 15*8= 120
4. Add all the numbers
360+120+80= 560
Surface area of a cylinder
1. Find the area of the circles
Area = 3.14 times diameter
Circumference = 3.14 * diameter
Area of the circle= 3.14*10*10=314 plus the other circle 314 = 628
2. Find the area of the rectangle
45*3.14 *20 = 2826
3. Add
2826 + 628 = 3454
How to find the surface area of a square pyramid
1.
2.
3.
4.
Find the area of the square 3*3= 9
Find the area of the triangle 3 * 5= 15 divided by 2 = 7.5
There are 4 triangles so multiply 7.5*4 witch equals 30
Add 30+9 = 39