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# The Total Surface Area of a Hollow Cylinder Which is Open from Both Sides is 4620 Sq. Cm,Area of Base Ring is 115.5 Sq. Cm and Height 7 Cm. Find the Thickness of the Cylinder - CBSE Class 9 - Mathematics

ConceptSurface Area of a Right Circular Cylinder

#### Question

The total surface area of a hollow cylinder which is open from both sides is 4620 sq. cm,area of base ring is 115.5 sq. cm and height 7 cm. Find the thickness of the cylinder

#### Solution

Let the inner radii of hollow cylinder rcm
Outer radii of hollow cylinder Rcm
Then,

2πrh + 2πRh +2πR^2  - 2πr^2 = 4620 → (1)

πR^2 =πr^2 =115.5→(2)

⇒ 2πh(R+r)+2(πR^2-πr^2)=4620 and πR^2-m^2 = 115.5

⇒2πh(R+r)+231=4620 and π(R^2-r^2)=115.5

⇒2π× 7(r+R)=4389 and π(R^2-r^2)=115.5

⇒π (R+r)=313.5 and π (R+r) (R-r)=115.5

⇒(π(R+r)(R-r))/(π(R+r))=115.5/313.5

⇒ R-r=7/19cm.

Is there an error in this question or solution?

#### APPEARS IN

RD Sharma Solution for Mathematics for Class 9 by R D Sharma (2018-19 Session) (2018 to Current)
Chapter 19: Surface Areas and Volume of a Circular Cylinder
Ex.19.10 | Q: 5 | Page no. 8
Solution The Total Surface Area of a Hollow Cylinder Which is Open from Both Sides is 4620 Sq. Cm,Area of Base Ring is 115.5 Sq. Cm and Height 7 Cm. Find the Thickness of the Cylinder Concept: Surface Area of a Right Circular Cylinder.
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