A semicircular sheet of paper of diameter 28 cm is bent to cover the exterior surface of an open conical ice-cream cup. The depth of the ice-cream cup is :
A. 8.12 cm
B. 10.12 cm
C. 12.12 cm
D. 14.12 cm
Answer: Option C
Solution(By Examveda Team)
Slant height of the cup, l = Radius of sheet = 14 cmCircumference of the base :
= Circumference of the paper sheet
= $$\left( {\frac{{22}}{7} \times 14} \right)$$ cm
= 44 cm
Let the radius of the base of the cone be r cm
$$\eqalign{ & \therefore 2\pi r = 44 \cr & \Rightarrow r = \frac{{44 \times 7}}{{2 \times 22}} \cr & \Rightarrow r = 7 \cr & {\text{Height, h:}} \cr & = \sqrt {{l^2} - {r^2}} \cr & = \sqrt {{{\left( {14} \right)}^2} - {{\left( 7 \right)}^2}} \cr & = \sqrt {147} {\text{ cm}} \cr & = 7\sqrt 3 {\text{ cm}} \cr & = 12.12{\text{ cm}} \cr} $$
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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