Triangles
What is the formula for the area of a triangle?
A=base*height/2 or A=1/2base*height
What is the formula of the area of a parallelogram?
A=Base*height
What is the definition of area?
One way to describe the size of a 2-dimensional shape.
What is a polygon?
A closed 2-dimensional shape with straight sides that do not cross each other.
What is the definition of surface area?
The measurement of all the sides of a 3-dimensional shape.
A triangle makes up half of a .
Square, Rectangle, or Parallelogram
What shape makes up a parallelogram?
Triangles
What is the formula of the area of a triangle?
A=b*h/2
What are the possible shapes that a polygon could be decomposed into?
Parallelogram + Triangle
Triangle + Triangle
Rectangle + Triangle
How do you find the surface area of a 3-dimensional shape?
1st, calculate the area of each side.
2nd, add those sides together.
3rd, write the answer in units cubed.
A triangle with a base of 10 cm and a height of 20 cm has an area of what?
100 cm2
What shapes are parallelograms?
Rectangles and Squares
What is the formula for the area of a parallelogram?
A=b*h
What is the area of a polygon with 3 sides that has a base of 5 cm and a height of 6 cm?
15 cm2
What is the surface area of rectangular prism with a base of 4 cm, height of 2 cm, and a width of 3 cm?
52 cm2
If a triangle has a base of 12 ft and a height of 5 ft, what would the area be?
30 ft2
If a parallelogram has a base of 3 inches and a height of 6 inches, what is the area?
18 in2
How would you find the area of a shape that is not a typical shape? Describe what you would do to find the area.
Varied answers.
Decompose the shape into various shapes that you can use a formula for. Once you have decomposed them and found the area of those shapes, then add them together to get the area of the entire shape.
What is the area of a polygon with 4 sides with a base of 10 ft and a height of 4 ft?
40 ft2
If we have a net with a square base and 4 equal triangles, when folded up, what type of polyhedron would it form?
A Square Pyramid
There are 3 triangles with the same area, they must have the same base and height. (True or False- if false, why?)
False. They can have different bases and heights, they just have to equal the same area.
If a parallelogram has an area of 40 in2 and a base of 5 inches, what is the height?
8 inches
What are the two area strategies?
Decomposing a shape
Rearranging a shape
If a polygon has an area of 50 ft2, 4 sides, and a base of 10 ft, what is the height?
5 ft
If a net has 2 triangle bases and 3 rectangular sides, what polyhedron would it make?
Triangular Prism