1. Working with Shapes in Two Dimensions
Two-Dimensional Objects

2. Perimeter The distance around a figure.
Think of perimeter as the distance you would travel if you walked around the edge of the figure.
To find the perimeter, add the lengths of the sides of the figure.

3. Area
When working with flat figures you can calculate how much surface is enclosed within the boundaries.
Area is measured with square units: such as square inches, square feet, and square meters.
Formulas are used to calculate total area of a figure.

4. Rectangle
Has four sides and four right angles. Opposite sides of each pair are parallel and the same length.
To calculate the area of a rectangle multiply the length times the width.
l x w

5. Square
A square has 4 sides, all the same length, and four right angles. Opposites sides of each pair are parallel.
To calculate the area of a square multiply the length of one side times itself
(side squared)

6. Parallelogram
Has four sides. Opposite sides of each pair are parallel and the same length.
To calculate the area of a parallelogram multiply base times the height.
b x h

7. Right Triangle Triangle has three sides with one right angle.
To calculate the area of a triangle, multiply one-half times the length of the base times the height.
1/2bh

8. Trapezoid Has four sides. Only one pair has parallel opposite sides.
To calculate the area of a trapezoid multiple ½, add the bases, and multiply by the height.
½ (b1 + b2)h

9. Circle
A circle is formed by points that are all the same distance away from a certain point
To calculate the area of a circle multiply pi times radius squared.
Pi(r)2