The length of canvas 1.1 m wide required to build a conical tent of height 14 m and the floor area 346.5 sq.m is :
A. 490 m
B. 525 m
C. 665 m
D. 860 m
Answer: Option B
Solution(By Examveda Team)
$$\eqalign{ & \pi {r^2} = 346.5 \cr & {r^2} = \left( {346.5 \times \frac{7}{{22}}} \right) \cr & {r^2} = \frac{{441}}{4} \cr & {r^2} = \frac{21}{2} \cr & \therefore l = \sqrt {{r^2} + {h^2}} \cr & \,\,\,\,\,\,\, = \sqrt {\frac{{441}}{4} + {{\left( {14} \right)}^2}} \cr & \,\,\,\,\,\,\, = \sqrt {\frac{{1225}}{4}} \cr & \,\,\,\,\,\,\, = \frac{{35}}{2} \cr} $$So, area of canvas needed :
$$\eqalign{ & \pi rl = \left( {\frac{{22}}{7} \times \frac{{21}}{2} \times \frac{{35}}{2}} \right){{\text{m}}^2} \cr & \,\,\,\,\,\,\,\,\,\,\, = \left( {\frac{{33 \times 35}}{2}} \right){{\text{m}}^2} \cr} $$
∴ Length of canvas :
$$\eqalign{ & = \left( {\frac{{33 \times 35}}{{2 \times 1.1}}} \right){\text{ m}} \cr & = 525{\text{ m}} \cr} $$
Related Questions on Volume and Surface Area
A. 12$$\pi$$ cm3
B. 15$$\pi$$ cm3
C. 16$$\pi$$ cm3
D. 20$$\pi$$ cm3
In a shower, 5 cm of rain falls. The volume of water that falls on 1.5 hectares of ground is:
A. 75 cu. m
B. 750 cu. m
C. 7500 cu. m
D. 75000 cu. m
A. 84 meters
B. 90 meters
C. 168 meters
D. 336 meters
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