7th Grade Math

Use a soup can. Measure and record the

height of the can.

Label the top and bottom faces using

a blue marker. Label the curved side

using a red marker.

Carefully peel off the label of the soup can and tape it to a

piece of paper. Trace the top and bottom faces so they are

adjacent to the label.

top

bottom

side

the Results

5. Name the shapes that make up the net of the container.


6. Find the diameter of the top of the container and use it to find the perimeter
   or circumference of that face. Find the area of the top and bottom faces.


7. How is the circumference of the top face of the container related to the rectangle?


8. How could the area of the label be found with the circumference of the top
   face of the container? Calculate the area of the label.


9. Add the area of the label to the sum of the areas of the two circular bases.


10. MAKE A CONJECTURE Write a formula for finding the area of all the surfaces of a
    cylinder given the measures of its height and the diameter of one of its bases.

and Apply

11. CAKES Cake decorators use sheets of icing called fondant. Desa is
    decorating a rectangular cake that is 24 inches by 18 inches by 4 inches.
    What is the area of the sheet of fondant that she will need to cover the
    exposed parts of the cake?


12. FIRE PIT James is forging a cylindrical iron fire pit. He wants the pit to be
    3 feet in diameter and 2 feet high with the bottom closed and the top open.
    How much iron will be used to forge the pit? Round to the nearest tenth.

Lesson 2A Surface Area 581

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