# Plz help..The internal and external diameters of a hollow hemispherical vessel are 14 cm and 21 cm respectively. The cost of silver plating of 1 sq. cm of its surface is Rs 1.60. Find the total...

Plz help..

The internal and external diameters of a hollow hemispherical vessel are 14 cm and 21 cm respectively. The cost of silver plating of 1 sq. cm of its surface is Rs 1.60. Find the total cost of silver plating the vessel all over.

Asked on by itssnigdha

### User Comments

neela | High School Teacher | (Level 3) Valedictorian

Posted on

The hemispherical vessal has two surfaces. Internal and external.

Let R and r be the eadius of the internal and external radius. Also radius is half the diameter.

The outer surface area of the hemisphere = (1/2)( 4*pi*R^2 ) =2 pi*(21/2)^2 = 2770.88472/4 sq cm = 692.72118

The area of the internal hemisphere = (1/2)*(4pir^2) = 2pi*r^2 = 2pi*(14/2)^2 = 1231.50432/4 sq cm = 307.8760801 sqcm

The ring or edge area = pi *R^2-Pir^2 = pi*(R^2-r^2) = pi*(21^2-14^2)/4 =769.6903001/4 = 192.422575 .

Thererefore the total area = 692.72118+307.87608+192.422575  = 1193.019835 sq cm

Therefore the plating cost @ Rs 1.60 for the above total area = 1193.019835 sq cm * Rs1.6sqcm = Rs 1908.83

kanishkporwal | Student, College Freshman | (Level 2) eNoter

Posted on

hi,

This is a basic math problem if you are facing trouble solving this than you should hire one of the online math tutors available on internet.At this students can submit their questions online to get the answers. They can also get elaborate explanations on particular topics required from the tutors. The students can observe the solved examples online and solve similar problems. They can also clarify their doubts regarding the concepts involved from the tutors immediately.

abertfrank | eNotes Newbie

Posted on

Hi, for any homework help, assignment help, dissertation help, visit our website http://www.helpwithassignment.com. We offer online tutoring, assignment help, homework help, dissertation help and thesis help in almost all the subjects. We offer services for a range of subjects for K-12, College and University.