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Quiz Wed'

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If the farmer uses this fence to enclose a circular flower garden, what will the ... The surface area is the area needed to cover all of the faces of a 3-D object. ... – PowerPoint PPT presentation

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Title: Quiz Wed'


1
4/28
  • Quiz Wed.

2
Homework Issues
3
14. A farmer has a fence that encloses a square
pot with an area of 36 sq. meters.
  • If the farmer uses this fence to enclose a
    circular flower garden, what will the area of the
    garden be?
  • There are two ways to think about this.
  • How do we answer these?

Way 2
Way 1
36 in2
Uses the same fence
4
10.3
5
1. Surface Area
  • The surface area is the area needed to cover all
    of the faces of a 3-D object.

6
  • Use some of the 3-D manipulatives (the colorful
    ones we used before)
  • Play around with finding the surface areas of
    some shapes.
  • How did you go about doing this?

7
  • Notice that looking at the nets of the object
    makes it easier to think about the surface areas.

8
2. Surface area of a prism the sum of all the
areas of all of its faces.
  • Find the surface areas of the prisms shown below.
  • Work with a partner. What do you think?

9
Again, we can look at nets.
4
12
12
10
  • Can we find an easier way to determine the
    surface area?

11
Notice that the length of this rectangle is the
perimeter of the base.
Height 12
12
  • The Surface area of a prism
  • 2Bph
  • Where B is the area of the base, p is the
    perimeter of the base, and h is the height of the
    prism.

13
3. The Surface Area of Cylinders
  • How can we do this?
  • How do we make a net for this?

14
  • Surface area of a cylinder

15
4. The Surface Area of Pyramids
  • Were only going to work with pyramids whose
    triangular lateral faces are congruent. The apex
    is above the center of the base.
  • Find the SA of the pyramid below.

l5 cm, s6cm
What is this angle here?
16
Area of each triangle ½(6)(5)
l5, s6
Notice that 4(6) is the perimeter of the square.
17
  • The SA of a pyramid B 1/2 pl
  • B Area of Base
  • p perimeter
  • l slant height

18
Find the surface area of the below pyramid
s6 in, and the height of the pyramid is 1 ft.
19
5. The Surface area of a Cone
  • Lets use what we have from the pyramid
  • SA of pyramid B 1/2 pl

20
  • SA of a cone

21
  • Find the SA of

7 in
5 in
3 in
22
6. The Surface Area of Spheres.
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