Post on 27-Dec-2015
Rectangles
0Think about this classroom. The floor is a rectangle. 0 If we measured the perimeter, what would that look
like?
0 If we painted the floor, what geometry term are we measuring?
Definitions
Perimeter: the sum of the lengths of the sides of a polygon
Area: the number of square units a polygon encloses
Margaret’s garden is a square 12 ft on each side. Margaret wants a path 1 ft wide around the entire garden. What will the outside perimeter of the path be?
P = 4s
P = 4(14) = 56
Because the path is 1 ft wide, increase each side of the garden by 1 ft. s = 1 + 12 + 1 = 14
Extension #1:
Find the area of the figure below.
Step #1: Divide the figure into squares and rectangles:
Extension #2:
AR = bhAR = (15)(5)AR = 75
AS = s2
AS = (5)2
AS = 25
A = 75 + 25 + 25 A = 125
Step #2: Find each area. Then add the areas.
C = 2 π (6.5)
C = 13π
C = 13 40.840704 ≈ 40.8
C = 2 π r
⨀ G has a radius of 6.5 cm. Find the circumference of ⨀ G in terms of π. Then find the circumference to
the nearest tenth.
Example: