Question

the cost of painting the total surface area of a cone at 25 paise per cm square is 176 rupees.find the volume of the cone ,if its slant height is 25 cm​

Answer 1

cost - 25/100 rupees per cm^2    or    1/4 rs. per cm^2

total cost = 176 rs.

total cost/ cost per cm^2 = cm^2       or    total surface area of cone

704 cm^2 = pi*r*(r+l)

704 = 22/7 * r(25+r)

224 = r^2 + 25r

r^2 + 25r - 224 = 0

(r-7)(r+32) = 0

r = either 7 or -32

length is not negative so radius = 7cm

V = 1/3*pi*r^2*h

h = root of (l^2 - r^2)

h = 24cm

V = 1/3*22/7*24*32*32

V = 25,746.2857

so Volume = approx. 25,746.29 cm^3

Answer 2

Given : The cost of painting the total surface area of a cone at 25 paise per cm square is rupees 176. To find : The volume of the cone if its slant height is 25 cm? Therefore, The volume of the cone is 1232 cm.