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How do you find the TSA of a right circular cylinder

GeneralClass 12AllAnswered 27 Mar 2026
Answer

To find the Total Surface Area (TSA) of a right circular cylinder with radius r and height h, use the formula TSA = 2πr(h + r) or equivalently TSA = 2πrh + 2πr², which accounts for the curved lateral surface (2πrh) plus both circular bases (πr² each, totaling 2πr²). Measure or identify the cylinder's radius (from center to edge of circular base) and height (perpendicular distance between bases), ensure units are consistent, then substitute into the formula and calculate.

Step-by-step example: Find TSA of a cylinder with radius 5 cm and height 12 cm. TSA = 2πr(h + r) = 2π(5)(12 + 5) = 2π(5)(17) = 170π ≈ 534.07 cm². Breaking it down: curved surface area = 2πrh = 2π(5)(12) = 120π ≈ 376.99 cm², area of both bases = 2πr² = 2π(25) = 50π ≈ 157.08 cm², total = 534.07 cm². The formula's structure reflects that you're essentially "unrolling" the cylinder: the curved surface unwraps into a rectangle with width 2πr (circumference) and height h, giving area 2πrh, while each circular base contributes πr². Understanding this decomposition helps remember the formula and apply it correctly. For hollow cylinders (just the curved surface, no bases—like a pipe section), use only 2πrh. For half-cylinders, calculate full cylinder TSA and adjust appropriately, adding the rectangular cross-section area. Practical applications include: calculating paint for cylindrical tanks, determining material for manufacturing cans or pipes, estimating heat transfer surface area, or analyzing packaging requirements. Common mistakes include: forgetting to multiply by 2 for both bases, using diameter instead of radius, inconsistent units, or omitting bases when TSA is required. Always verify whether the problem wants total surface (including bases) or just lateral/curved surface (excluding bases), as this determines whether you use full TSA or just CSA. The right circular cylinder is among the most common shapes in engineering, manufacturing, and everyday objects, making this TSA calculation widely applicable.

General · Class 12