Verified by Ajay Kumar
The total surface area of a hemisphere is 462 cm². What is its curved surface area? (Use \(\pi=\frac{22}{7}\))
283 cm²
329 cm²
308 cm²
258 cm²
Answer: C
Solution: Total surface area of a hemisphere \(=3\pi r^2=462\). Thus, \(r^2=\frac{462\times7}{3\times22}=49\). Curved surface area \(=2\pi r^2=2\times\frac{22}{7}\times49=308\) cm². Trick: Hemisphere TSA is \(3\pi r^2\), while its curved surface area is \(2\pi r^2\).
एक अर्धगोले का कुल पृष्ठीय क्षेत्रफल 462 सेमी² है। इसका वक्र पृष्ठीय क्षेत्रफल कितना है? \(\left(\pi=\frac{22}{7}\text{ लें}\right)\)
283 सेमी²
329 सेमी²
308 सेमी²
258 सेमी²
उत्तर: C
हल: अर्धगोले का कुल पृष्ठीय क्षेत्रफल \(=3\pi r^2=462\)। इसलिए \(r^2=\frac{462\times7}{3\times22}=49\)। वक्र पृष्ठीय क्षेत्रफल \(=2\pi r^2=2\times\frac{22}{7}\times49=308\) सेमी²। ट्रिक: अर्धगोले का कुल पृष्ठीय क्षेत्रफल \(3\pi r^2\) और वक्र पृष्ठीय क्षेत्रफल \(2\pi r^2\) होता है।
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