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A student in Brisbane is designing a cylindrical can-cooler made from a single piece of fabric that wraps around a right circular cylinder with a height of 97 cm and a base radius of 84 cm. The cooler must cover the lateral surface only, and the fabric is cut from a rectangular sheet with no waste.
What is the exact surface area of the lateral surface of the cylinder, in square centimetres, expressed in terms of π? Use the formula for lateral surface area of a cylinder: SA = 2πrh, where r is the radius and h is the height.
Provide the exact answer as a simplified expression involving π.
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Explanation
Worked solution and answer (click to reveal)
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Worked solution
- The problem requires finding the lateral surface area of a right circular cylinder with height h = 97 cm and base radius r = 84 cm.
- The lateral surface area of a cylinder is given by the formula SA = 2πrh, which applies because the surface is curved and wraps around the cylinder without top or bottom.
- Substitute the given values into the formula: SA = 2 × π × 84 × 97.
- First, compute the product of the constants: 2 × 84 × 97.
- Calculate 2 × 84 = 168.
- Now compute 168 × 97. Use distributive property: 168 × (100 - 3) = 168×100 - 168×3.
- 168 × 100 = 16,800.
- 168 × 3 = 504.
- Subtract: 16,800 - 504 = 16,296.
- Now include π: SA = 16,296π cm².
- The expression 16,296π is already simplified and exact, as no common factors exist between 16,296 and π.
- The lateral surface area of the cylinder is exactly 16,296π square centimetres.
Reference answer: 16296π cm²
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