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प्रश्न
A toy is in the form of a cone mounted on a hemisphere of common base radius 7 cm. The total height of the toy is 31 cm. Find the total surface area of the toy.
उत्तर
Radius of the hemisphere = Radius of the cone = 7 cm
Height of the cone = (31 - 7)cm = 24 cm
Slant height of the cone , `l =sqrt("r"^2 + "h"^2)`
`= sqrt((7)^2 + (24)^2)`
`=sqrt(49+576)`
`=sqrt(625)`
= 25 cm
Total surface area of the toy = (Curved surface area of the hemisphere) + (Curved surface area of the cone)
=2πr2 + πrl
= π × r × (2r + l)
`=22/7xx7xx(14+25) "cm"^2`
= 858 cm2
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Match the column:
| (1) surface area of cuboid | (A) πr2h |
| (2) surface area of closed right cylinder | (B) 2πr(h + r) |
| (3) Total surface area of right cone | (C) πrl + πr2 |
| (4) Total surface area of hemisphere | (D) 3πr3 |
| (E) 3πr2 | |
| (F) 2[lb + bh + lh] |
