Area, Perimeter, and circumference
Overview: In this lesson you will learn how to find the area of shapes, the circumference of shapes and the perimeter of shapes.
How to find the area of shapes
Area: space inside of a shape.
To find area you use the method length times width equals area or L•W=A
Definition: the inside space of a two-dimensional figure.
To find area you use the method length times width equals area or L•W=A
Definition: the inside space of a two-dimensional figure.
What an area problem looks like
Area=Length•Width. Important numbers21 & 53
Fill in variable letters (L,W). L•W=?
53=L
21=W
Answer: 53•21=113 inches.
Fill in variable letters (L,W). L•W=?
53=L
21=W
Answer: 53•21=113 inches.
How to Find the Perimeter of Shapes
Perimeter: Outer boundary of a shape. (not a circle) To find area you use the method L+W+L+W=P.
Definition:the border or outer boundary of a two-dimensional figure.
Definition:the border or outer boundary of a two-dimensional figure.
What a perimeter problem looks like
Perimeter=L+W+L+W
Important numbers:73,& 73.
variable numbers. (L,W,L, and W).
Variable problem is L+W+L+W=?
L=50
W=73
50+73+50+73=246 inches.
Important numbers:73,& 73.
variable numbers. (L,W,L, and W).
Variable problem is L+W+L+W=?
L=50
W=73
50+73+50+73=246 inches.
How to find the circumference
Circumference: the distance AROUND the circle
Definition:the outer boundary, especially of a circular area; perimeter:
C=pi•diameter
Definition:the outer boundary, especially of a circular area; perimeter:
C=pi•diameter
What a circumference problem looks like
2 different ways to find the circumference: pi (3.14) times the diameter,second is 2 times pi (3.14) times radius
Radius is half the size of the diameter and the diameter is 2 times larger than the radius.
Radius is half the size of the diameter and the diameter is 2 times larger than the radius.
Diameter and Radius example problems
2 ways to find the circumference:
pi•D
pi•R
Option number one example: 3.14•16 (diameter)
Option number two example:2•3.14•8 (radius)
Option number one answer: 50.24
Option number two answer: 50.24
Do you see the resemblance? :)
pi•D
pi•R
Option number one example: 3.14•16 (diameter)
Option number two example:2•3.14•8 (radius)
Option number one answer: 50.24
Option number two answer: 50.24
Do you see the resemblance? :)