Iron Works Worksheet #2 KEY
Name __________________________________ Date__________
Complete each of the problems (opportunities to learn). Be sure to use
appropriate units with your opportunities. Use Pi = 3.14.
1. The diameter of a tree trunk is 14 inches. Find the
circumference?__43.96inches_______
Pi times diameter equals circumference
3.14 · 14” = 43.96inches
2. The radius of a wheel is 15 centimeters. Find its circumference?
__94.2centimeters______
Pi times two times radius equals circumference
3.14 · 2 · 15 = 94.2cm
3. How much edging is needed to enclose a circular flower garden that as a
diameter of 12 meters?___37.68meters__
Pi times diameter equals circumference
3.14 · 12m = 37.68m
4. Mrs. Wrong decided to build a circular drive way and she decided that that
she would put a sturdy edging around the center portion to make a flower
garden. The diameter of the center portion is 56 feet. How many feet of flat
metal will be needed to edge the circle? 175.84feet
Pi times diameter equals circumference
3.14 · 56’ = 175.84ft
5. A landscape designer recommends that a short decorative fence be placed
around a circular landscaped area. If the area has a diameter of 24.5 feet
how many feet of fence is needed? 76.93_feet
Pi times diameter equals circumference= 3.14 · 24.5’ = 76.93ft
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6. You have a rope making a circle that is 88 feet in diameter how long is this
rope if you pulled it straight? _____276.32feet________
Pi times diameter equals circumference
3.14 · 88’ = 276.32’
7. You have a pop can with 6 rubber bands evenly spaced on the can. The
can has a radius of 1.75 inches, how many linear inches of rubber bands
are there on the can? 65.94 linear inches
Radius times two equals diameter
1.75” · 2 = 3.5”
Pi times diameter equals circumference
3.14 · 3.5” = 10.99”
To find the linear inches take circumference times Six
10.99” · 6 = 65.94 linear inches
8. You have a tree in your yard that is 60 inches around. What is the diameter
of the tree? _____19.1 inches________
Circumference divided by Pi equals diameter
60”/3.14 = 19.1”
9. Joe Wright is a big hay farmer who bales a large amount of hay but has a
small amount of barn space. He is going to stack the bales in the barn on
their ends and would like cover the 5’X5’ bale ends and leave the space
between the bales uncovered. How many square feet of plastic will be
needed to cover the ends of the bale? ____19.625square feet __
Radius squared times Pi equals area of a circle
(2.5’)(2.5’) · 3.14 = 19.625ft2
10. The front cover of your book measures 8.5 inches by 11 inches. How many
square inches is the area covered by the front cover of your book?
______93.5 square inches_____________
Length times width equals square units = 8.5in · 11in = 93.5in2
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11. You have a rectangular hayfield measuring 800 yards by 375 yards. What
is the perimeter of the field? ___2350 yards___ What is the area of the
field? 300,000 square yards
Two times length plus two times width equals perimeter
(2)800 + (2)375 = 2350yd
Length times width equals square units
800yd · 375yd = 300,000yd2
12. The shop is 19 feet wide and 42 feet long. What is the perimeter?
__122_feet___ What is the area? 798 square feet_
Two times length plus two times width equals perimeter
(2)42 + (2)19 = 122’
Length times width equals square units
42’ · 19’ = 798ft2
13. Find the volume of a circular pool if the diameter is 24 feet and the height of
the pool 4 feet? _____1808.64 cubic feet__
Diameter divided by two equals radius
24’/2 = 12’
Pi times radius squared times height equals Volume
3.14 · (12’)(12’) · 4’ = 1808.64ft
Bonus:
How many liters does a cylinder hold if the diameter is 40 centimeters and the
height is 60 centimeters? _75.36 Liters___
(Use the formula for the volume of a cylinder, V = Pi · r2 · h. To change
centimeters cubed to liters: Use 1 cm3 = 1 ml, 1000 ml = 1 L)
Example: 5 cm3 = 5 ml, 5 ml/1000 ml = 0.005 L
Diameter divided by two equals radius
40 cm/2 = 20 cm
Pi times radius2 times height equals Volume
3.14 · (20 cm)2 · 60 cm = 75360 cm3
1 cm3=1 ml
75360 cm3 = 75360 ml
1000 ml = 1 L
75360 ml / 1000 ml = 75.36 L
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