This document summarizes formulas for calculating the perimeter and area of different shapes. It explains that the perimeter of polygons is calculated by adding all the sides, and the circumference of a circle is 2πr, where r is the radius. It then discusses formulas for calculating the area of parallelograms, triangles, trapezoids, and circles. The area of parallelograms and rectangles is equal to the base times the height. The area of a triangle is 1/2 the base times the height. The area of a trapezoid is 1/2 the sum of the bases times the height. The area of a circle is πr2, where r is the radius. It concludes with example problems

1. Ch5.2_5.4_AreasAndPerimeter.notebook November 14, 2011
Chapter 5.2 AND 5.4
Perimeters and Area

2. Ch5.2_5.4_AreasAndPerimeter.notebook November 14, 2011
Perimeter: The distance around a figure
Polygons ­ add all sides together
Circles ­ "circumference"
π ≈ 3.14
2πr r = radius

3. Ch5.2_5.4_AreasAndPerimeter.notebook November 14, 2011
Area ­ the 2­dimensional space within a shape
Parallelograms ­ Area = base x height
A = b h
This is true for ALL p­grams,
rhombuses, rectangles, and
squares
NOTE: The height is PERPENDICULAR
to the base
h
h
h
h
Triangles
A = 1 base x height
2
4 ft 7 ft
10 mm
12 mm 3 ft

4. Ch5.2_5.4_AreasAndPerimeter.notebook November 14, 2011
Trapezoids
1
A = h (base 1 + base 2)
2
3 in
Find the area.
2 in
5 in
Circles
A = π r2 π≈ 3.1416
r is the radius
2 cm

5. Ch5.2_5.4_AreasAndPerimeter.notebook November 14, 2011
Examples
Page 218
#12 ­ 15 all
#17 ­ 22 all