Geo Day 2 Area of Rectangle, Parallelograms and Triangles.notebook
Day 2: Area & Perimeter of Rectangles, Parallelograms, & Triangles
Objecve: 1. You will be able to use a plan to solve problems that involve the perimeters and areas of rectangles, parallelograms and triangles.
Steps for Problem Solving
1. Always draw a diagram with labels to illustrate the problem.
2. Always state the formula you are planning to use.
3. Identify the knowns & unknowns for each variable in the formula.
4. Plug the knowns into the equation.
5. Solve for the unknown using algebra.
6. Be sure to include a label with your answer.
*You are expected to follow and show the steps listed above.
Perimeter Formula for a Parallelogram or Rectangle:
*Remember that perimeter is a linear funcon so the labels are always: Ex: cm, in, yd, . . . .
Area Formula for a Parallelogram or Rectangle:
*Remember that this is a 2‐Dimensional funcon so all labels are always squared!!
Ex: cm2 in2 yd2
Area of a Triangle:
Formula:
Triangles and their heights (altudes) can have mulple appearances:
Example 1 :
Find the perimeter and area of the rectangle.
Aug 4­8:06 PM
6 cm
3.5 cm
Geo Day 2 Area of Rectangle, Parallelograms and Triangles.notebook
Example 2:
A parallelogram has a perimeter of 80 inches. If the length is 22 inches, what is the parallelogram’s width?
12m
Example 3:
Find the area of the parallelogram.
6m
20m
Aug 4­8:13 PM
Geo Day 2 Area of Rectangle, Parallelograms and Triangles.notebook
Example 4:
The area of a rectangular garden is 84 ft2 . If the base of the garden is 7 ft, what is its height?
Example 5:
Solve for the area of the figure. Example 6:
What is the height of a triangle whose area is 36 in 2 and whose perpendicular base is 12 in.?
Aug 4­8:29 PM
Geo Day 2 Area of Rectangle, Parallelograms and Triangles.notebook
Geo Day 2 Area of Rectangle, Parallelograms and Triangles.notebook