A sphere is cut into 4 identical pieces after it was painted. What is the ratio of the painted area to the unpainted area?

• after cutting into four pieces we have each piece having two semicircular planes perpendicular to each other giving a (unpainted)surface area of pi*r^2..hence ratio is 1:1
• 10 years agoHelpfull: Yes(22) No(2)
• after cutting sphere into 4 parts each part looks like a cone.
  
  area of cone with eual radius and height is 3(pi)r^2/2
  for 4 cones 3*(3(pi)r^2/2) = 6(pi)r^2
  this area was not painted will obtain from subtacting area of sphere from above cone area i.e 6(pi)r^2 - 4(pi)r^2 = 2(pi)r^2
  unpainted area
  area of sphere = 4(pi)r^2
  this much are was painted.
  
  ratio to the painted to unpainted is 2;1
  
  ans:2:1
• 10 years agoHelpfull: Yes(16) No(12)
• Sphere is painted at first then cut
  After being cut.. we have 4 parts
  now each part has two unpainted surfaces.... just imagine this side in ur mind...
  one surface will have area= (pi*r^2 )/2
  hence one part have total unpainted area= 2*[(pi*r^2)/2]= pi*r^2
  
  therefore 4 parts will have combined area = 4*(pi*r^2)
  
  sphere itself have surface area= 4*(pi*r^2)
  
  hence ratio is 1:1 ... :)
• 9 years agoHelpfull: Yes(16) No(1)
• 1:3 painted sphere /4=four cone shaped parts with 3 side unpainted 1 side painted
  
• 10 years agoHelpfull: Yes(6) No(9)
• after cutting sphere into 4 parts each part looks like a cone.
  
  area of cone with eual radius and height is 3(pi)r^2/2
  for 4 cones 3*(3(pi)r^2/2) = 6(pi)r^2
  this area was not painted.
  
  area of sphere = 4(pi)r^2
  this much are was painted.
  
  ratio to the painted to unpainted is 4:6 i.e 2:3
  
  ANS:2:3
• 10 years agoHelpfull: Yes(4) No(9)
• 4:2
  the total sides are 6.and when it is cut each sphere has 4 painted side and 2 unpainted side.
  so, the ratio is 4:2=2:1
• 10 years agoHelpfull: Yes(3) No(5)
• we cut sphere in 3 axes. in every axis we get 2 circular planes with sphere radius.for every axis cutting we get 2^rr so total un painted area =6^rr
  ratio=painted/unpainted=(4^rr)/(6^rr)=2:3
• 10 years agoHelpfull: Yes(1) No(4)
• Answer 1:4
  actually sphere is cut into 4 identical pieces then 1 pieces is painted then remain 3 part are not painted then 1 part of sphere of 4 part are painted then ratio is 1:4
• 9 years agoHelpfull: Yes(1) No(4)
• answer is 1/4 because one sphare cut in to 4 equal pieces & then it was paintd
• 10 years agoHelpfull: Yes(0) No(6)
• After cutting the sphere into 4 parts,
  Each parts contain 2 unpainted and 1 painted area. so totally 4 parts 4*2=8 unpainted area and 1*4=4 painted area. ratio of painted area to unpainted area 4:8=1:2 so ans is 1:2
• 9 years agoHelpfull: Yes(0) No(5)
• total surface area of spear is = 2pi r ^2
  after cutting into 4 pieces surface area of each part is 2pi r*r / 4
  we have 3 unpainted part which would be 1/4 of area of a circle area, so total surface area is 3(pi r^2/4)
  now ratio = (2pi r*r/4)/(3.pi.r*r/4))=2/3
  
• 9 years agoHelpfull: Yes(0) No(4)