Cylinder: Take a moment to look around, and you will notice cylinders everywhere. From candles and soda cans to water tanks and pipes, this geometrical shape is all around us.
A cylinder is a three-dimensional object with two parallel circular bases connected by a smooth, curved surface. The word "cylinder" comes from the Greek word "kylindros," which means "roller" or "barrel." This name reflects the rolling nature of a cylinder, a characteristic that matches its shape in geometry. Since a cylinder is a three-dimensional geometric shape, it has two key properties: surface area, which measures its outer covering, and volume, which calculates the space it occupies.
Example 1: Find the total surface area of a cylindrical drum with a radius of 5 feet and height of 10 feet in square feet.
Solution: Given: R = 5 feet, h = 10 feetFormula:
TSA=2πr(h+r)Substitute the values:
TSA=2π×5×(10+5) TSA=2π×5×15=150π square feet TSA≈150×3.14=471.00 square feetExample 2: Find the curved surface area of a pillar with a radius of 4 cm and height of 9 cm.
Solution: Given: r=4 cm, h=9 cmFormula:
CSA=2πrhSubstitute the values:
CSA=2 × 22/7 × 4 × 9 CSA=2 × 22 × 36 ÷ 7 CSA=2×22×36÷7 CSA≈226.29 square cm (rounded to two decimal places)Example 3: Find the radius of a cylinder with a curved surface area of 352 sq. cm and height of 8 cm.
Solution: Given: CSA=352 sq. cm, h=8 cmFormula:
CSA=2πrhSubstitute the values:
352 = 2 × 22/7 × r × 8 352 = 352/7 r r= 352/ (2×22×8÷7) =352 × 7/ 352 r=7 cmsExample 4: Find the total surface area of a cylinder if the curved surface area is 198 sq. cm, and the radius is 6 cm.
Solution: Given: CSA=198 sq. cm, r=6 cmThe formula for CSA:
CSA=2πrhFind height (h):
198 = 2×22/7×6×h 198 = 264/7h h = 198 × 7/ 264 = 5.25Now calculate TSA:
TSA=2πr(h+r) TSA=2×22/7×6×(5.25+6) TSA=2×22/7×6×11.25 TSA≈ 2 × 3.14 × 6 × 11.25 = 424.1 sq. cm (rounded to two decimal places)Example 5: Find the volume of a cylindrical water tank with a radius of 7 feet and a height of 12 feet.
Solution: Given: r=7 feet, h=12 feetFormula for volume:
Volume (V)=πr 2 hSubstitute the values:
V=22/7 ×7 2 ×12 V=22/7 × 49 × 12 V=22×49×12÷7 V = 22 × 84 = 1848 cubic feet The volume of the water tank is approximately 1847.52 cubic feet.Related Articles | |
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