8th Grade Math Prompt

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8th GradeMath Prompt 5
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• 1. Which cylinder will hold the most liquid?
• d 14 in r 4 in
• h 3 in h 12 in
• cylinder A
  cylinder B
• Explain how you know.

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Notice this symbol in the corner of the page.
This tells you to use the ISTEP reference page
for a specific formula or conversion.
Volume of a cylinder V p r2 h (where p 3.14)
Cylinder A V (3.14)(72)(3) notice they gave the
diameter 14 in. and the
radius is half of the diameter or 7
in. Multiply all three numbers. V
(3.14)(49)(3) V 461.58 in3
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Notice this symbol in the corner of the page.
This tells you to use the ISTEP reference page
for a specific formula or conversion.
Volume of a cylinder V p r2 h (where p 3.14)
Cylinder B V (3.14)(42)(12) Multiply all three
numbers. V (3.14)(16)(12) V 602.88 in3
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• Cylinder A has a volume of 461.58 in3.
• Cylinder B has a volume of 602.88 in3.
• Cylinder B will hold the most liquid since is has
  the higher volume of the two.

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Scoring

• 3 pts. Correct formula procedure, answer and
• written explanation
• 2 pts. Two of above
• 1 pt. One of above
• 0 pts. None of above

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• Transform this shape over the y-axis. Label the
  vertices.
• See graph on following page.

Notice the symbol at the top left corner of the
page. This indicates that a ruler may be used
for best results.
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This is an approximation of the actual graph
given to students.
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To transform means to find the mirror image of
the shape. Sometimes we call this a flip.
To transform this shape, simply measure each
points distance to the axis and find the image
of the point on the other side of the axis.
Dont forget to label the image with A B C D
This indicates that these are vertices of an
image not the original shape.
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Scoring

• 2 pts. Correct picture and labeled vertices
• 1 pt. One of above
• 0 pts. None of above

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• 3. Zach wants to buy a widget factory. There are
  two possible factories Widgets-R-Us shows a
  profit with the following equation, P 2n, and
  Super Widgets shows a profit with this equation,
  P 2(n 4), where n number of days the
  widgets were sold. Graph the equations.
• Which company should Zach buy to get the most
  profit for his money? Explain.

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Make a table of values and graph each equation.
Remember, n number of days the widgets were
sold. P profit

• P 2n
• n P
• 1 2
• 4
• 8
• 4 16
• 5 32

P 2(n-4) n P 1 -6 2
-4 3 -2 4 0 5
2 6 4 7 6
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• Zach should pick Widgets-R-Us. This shows
  exponential growth, The profit grows larger and
  larger more quickly- it doubles every day. Super
  Widgets has a linear growth, and only grows by
  two each day.

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Scoring

• 3 pts. Correct graphs, answer and
• written explanation
• 2 pts. Two of above
• 1 pt. One of above
• 0 pts. None of above