Perimeter

The PERIMETER is the distance around the edges.

Think:   peRIMeter.

Find the PERIMETER:     this rectangle is 2 feet wide and 5 feet long
The perimeter would be:
  2' + 5' + 2' + 5' (This symbol:   '   indicates foot or feet)
    or
2 times 2'   plus   2 times 5'     (2 * 2') + (2 * 5')
    or
2 feet plus 5 feet TWICE:     2(2' + 5') = 2 * 7' = 14 feet


Although there are several formulas which can be used to find the perimeter, the easiest way to find the distance around the edges of a figure is to add all the sides together. When asked to choose an expression, you could figure out the actual quantity and then determine which of the expressions would yield that amount, or you may use the expressions, themselves, as a guide. Make a drawing whenever make the situation more clear (the drawing does not have to be accurate or 'to scale' it just needs to be usable).
Solve each problem; to check, click on the answer box:



Which expression shows the perimeter of a rectangle that is 20 cm long and 10 cm wide?   (Hint: MAKE A DRAWING!)
  1. 20 * 10
  2. 2(20 * 10)
  3. 2 * 20 + 2 * 10
  4. 4(20 + 10)
  5. 2 * 20 - 2 * 10
this rectangle is 10 centimeters wide and 20 centimeters long

(click on the answer box to check your results)




  1. What is the perimeter of a lawn that is 25 feet long and 20 feet wide?
    (HINT: You'd use this much fence around it.)
  2. Find the perimeter of a table cloth that is sixty inches square.
    (HINT: Each edge is 60" long.)
  3. Which expression shows the perimeter of a rug that is 4 yards in length and 3 yards in width?   Find the perimeter.
    1. (4 * 4) + (4 * 3)
    2. (2 * 4) - (2 * 3)
    3. 2(4 + 3)
    4. 4 * 3
    5. 2 * 4 + 3
  4. The length of a rectangle measures 60 meters and the width measures 40 meters.   Which of the following expressions shows the perimeter of the rectangle?   What is the perimeter?
    1. 2 * 60 * 40
    2. 60 * 40
    3. 4(60 * 40)
    4. (2 * 60) + (2 * 40)
    5. (2 * 60) - (2 * 40)




    ANSWERS:
    example:   C.   2 * 20 + 2 * 10   (60 centimeters)  
    1)   90 ft.  
    2)   240 in.  
    3)   C.   (14 yds)  
    4)   D.   (200 m)  


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