# Surface Area ad Volume of A Sphere - Class 9 : Notes

**(1) The set of all points in space which are equidistant the fixed point is called a sphere. The fixed point is called the center of the sphere and the constant distance is called its radius.****(2) For a sphere of radius r, Â we have
**

**(i) Â Surface area**

**If radius then**

*For Example:Â*Surface area

**(ii) Volume
**

**If radius then**

*For Example:Â*Volume

**(3) Curved surface area of a hemisphere of radius r is
**

**If a radius of hemisphere is , then**

*For Example:Â*Curved surface area of a hemisphere is

**(4) Total surface area of a hemisphere of radius r is
**

**If a radius of hemisphere is , then**

*For Example:Â*Total surface area of a hemisphere is

**(5) Volume of a hemisphere of radius r is
**

**If a radius of hemisphere is , then**

*For Example:Â*Volume of a hemisphere is

**(6) Volume of a spherical shell whose outer and inner radii are R and r respectively is given by**

**
**

**If Internal radii and external radii ,then**

*For Example:Â*