Post on 22-Feb-2016
description
transcript
Perimeter & Area
Measurement
Why do we measure objects?
Name a household object that can be measured?
Standard Measurement
Customary VS Metric
inches, feet, yards
VS
centimeters and meters
NON-Standard Measurement
Video example
of
non-standard
measurement
Perimeter
The perimeter is the distance around the outer limits of any two dimensional object.
PerimeterLook at the sides of an object.
They come together to make a shape.
PerimeterIf we want to know the distance around the shape, we measure the sides and add the lengths.
No matter how odd the shape is, you just add the sides together.
5”
4”
3”
2”
3”
1”5” + 3” + 3” + 1” + 2” + 4”or18”
AreaThe area of a figure measures the size of the region enclosed by the figure. This is usually expressed in terms of some square unit.
The area in INSIDE the figure and is expressed as square meters, square centimeters, square inches, or square feet.
Area
DifferenceWhat is the difference between
AREA and PERIMETER?
Why do people confuse AREA and PERIMETER?
MisconceptionsAfter giving definitions for perimeter and area, Mrs. Gonzalez gave her class the following problem.
Find the area and perimeter for the square that has a side of 4 inches.
MisconceptionsGianni, a student in the class drew the square on his paper:
Gianni indicated each side of the square was 4”.
4”
4”
4”
4”
MisconceptionsGianni wrote:
Perimeter is 16Area is 16
Is Gianni correct?Did Mrs. Gonzalez do anything wrong?
Misconceptions
What would you say to help Gianni?
MisconceptionsGianni and his best friend have both worked on this problem:
3”
3”
Given a square with side 3, find the area.
Misconceptions
3”
3”
Gianni said the area is 9 square inches and his friend Jen said it is 12 square inches.Who is right, Jen or Gianni? PROVE IT!
Misconceptions
3”
3”
How do you prove it?
1 2 34 5 67 8 9
MisconceptionsNext, Gianni & Jen work on this problem:
4”
7”
Find the area for this rectangle.
Misconceptions
Gianni said the area is 28 square inches and Jen said it is 22 square inches.
Who is right, Jen or Gianni?
4”
7”
Misconceptions
How did Gianni get his answer?
How did Jen get her answer?
4”
7”
Misconceptions
Who is right?
How do you prove it?
4”
7”
Misconceptions
36 square units
What does this mean?
MisconceptionsGianni looked at this problem and wrote
What did he do? Is he correct?
36 square units9 9
9
9
9 inches
MisconceptionsJen looked at this problem and wrote
What did she do? Is she correct?
36 square units 1296 inches
MisconceptionsBart laughed at both Jen and Gianni and wrote:
What did he do? Is he correct?
36 square units 36 ÷ 6 = 6
MisconceptionsChristy did the following:
What did she do? Is she correct?
36 square units 6 inches
MisconceptionsIf this represented a square pizza, what would be the length of the cheese stuffed crust?
36 square units
Vocabulary Foldable• Foldable
– Two 8.5 x 11 sheets of paper– Fold (hamburger style) both sheets– Put one folded sheet on top of other (with about
¼” of bottom sheet showing– Use pencil and place a mark approximately 1”
from each end
Vocabulary Foldable
• Make sure you mare each sheet in same place• Cut sheet 1 along seem TO the line you make from
each end• Cut sheet 2 between the lines
Vocabulary Foldable• Roll sheet 1 line a hotdog• Place in between sheet 2• Open so slits go inside ends of center cut sheet
You now have an 4 page (8 sided book)!
VocabularyLength
Width
Height
Base
Perimeter
Area
VocabularyPolygon
Quadrilateral
Rectangle
Square
Parallelogram
Rhombus
ReviewWhat have you learned?
Write 3 facts.