Question

a hollow hemispherical vessel has external and intrnwl radius as 43 cm and 42 cm . if cost of colouring it is 7 paise per square cm then find cost of painting
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Answer 1

ANSWER

EXTERNAL TOTAL SURFACE AREA = ΠR^2+2ΠR^2

= 3ΠR^2

= 3 × Π × 43^2

=17433.42 cm^2

INTERNAL TOTAL SURFACE AREA = ΠR^2+2ΠR^2

= 3ΠR^2

= 3 × Π × 42^2

= 16632 cm^2

TOTAL SURFACE AREA WITH HALLOW

= 17433.42 - 16632

= 801.42 CM^2

COST OF PAINTING PER SQUARE CM IS 7 paise

SO TOTAL = 801.42 × 7 = 5609.93 paise