Mensuration

 

 

 

Contents

 

Parts of Circle

 

Area of Circle

 

Area of Sector & Length of Arc

 

Area of Triangle 

 

Volume of Cylinder

 

Surface Area of Cylinder

 

Volume of Cones & Pyramids

 

Surface Area of Cones & Pyramids

 

Volume of Sphere

 

Surface Area of Sphere

  

Quiz

 

 

Geometry Main Page

Surface Area of Cylinder 

If you bend a rectangular sheet of paper, bringing two opposite sides together, you will get an open tube.

This is called an open cylinder. The surface area of this open cylinder is the area of its curved surface given by the product of the distance round the rim and the height. If the top and bottom of the cylinder are covered, we will have a closed cylinder.

Thus, the formula for volume of prism or cylinder is given by

V = area of base x height

Example 1

A thin can has a height of 15cm and a base radius of 7cm. It is filled with water. Find the total surface area in contact with the water. (Take p = 22/7) 

Surface area = pdh + pr2 
                      = 22/7 x 2(7) x 15 + 22/7 x 72 
                      = 814cm2 

Example 2
 
The curved surface area of a solid cylinder is 880cm2 and its height is 10cm. Find the circumference and area of the base of the cylinder.
 
Circumference = 880cm2/10cm
                    = 88cm
 
Radius = (88/p)/2
          = 44/2p 
 
Area = p x (44/2p)2
       = 616cm2 (3 s.f.)