1. 1.7 Introduction to Perimeter,
Circumference, & Area
p. 51

2. Rectangle
W
(width) • Perimeter
P=2l +2w
l
(length)
• Area
A=lw

3. Square
• Perimeter
P=4s
S
(side)
• Area
A=s2

4. Triangle
• Perimeter a c
h
P=a+b+c (height)
b
(base)
• Area
A= ½ bh

5. Circle
• Diameter
d=2r diameter
• Circumference
ra
di
us
C=2πr
• Area
A=πr2
** Always use the π button on the calculator;
even when the directions say to use 3.14.

6. Example: Find the perim. & area of the figure.
• P=2l +2w
P=2(5in)+2(3in)
P=10in+6in
5 in P=16in
3 in
• A=lw
A=(5in)(3in)
A=15in2

7. Ex: Find the perim. & area of the figure.
• P=4s
P=4(20m)
P=80m
20 m
• A=s2
A=(20m)2
A=400m2

8. Ex: Find the perim. & area of the figure.
• P=a+b+c
P=5ft+7ft+6ft
5 ft
P=18 ft
4 ft
7 ft
6 ft • A= ½ bh
A= ½ (7ft)(4ft)
A= ½ (28ft2)
A= 14ft2

9. Ex: Find the circumference & area of the
circle.
• C=2πr
C=2π(5in)
n
10i C=10π in
C≈31.4 in
• A=πr2
A=π(5in)2
A=25π in2
A≈78.5 in2

10. Assignment