Qs
External and internal diameter are 42 em and 35 cm respectively find
External and internal area and their difference.
Answers
Answered by
1
I think so this is answer
Answer
Internal diameter of spherical vessel =24 cm
External diameter of hemispherical vessel =25 cm
Internal radius =r=12 cm and External radius =R=12.5 cm
Total surface area to be painted
= External curved surface + Internal curved surface + Area of ring
=2πR
2
+2πr
2
+π(R
2
−r
2
)
=π(2R
2
+2r
2
+R
2
−r
2
)
=π(3R
2
+r
2
)
=
7
22
(3×12.5
2
+12
2
)
=
7
22
(468.75+144)
=
7
22
×612.75
=1925.78sq.cm
Rate of painting =5paise per sq.cm
Thus, cost of painting=Area×Rate=
100
1925.78×5
=Rs.96.29
Similar questions