A circular shaped ball with a diameter or radius is called a sphere.A diameter which is a straight line through the center of a sphere and with the end points on the boundary is called its diameter.

The section of the sphere by the plane is called a hemisphere. Letâ€™s see how to find the area of Hemisphere.

## Formula of Surface area of Hemisphere.

Total Surface area of Sphere (TSA) = 4Ï€r |

Curved Surface area of Hemisphere(CSA) = 2Ï€r |

Total Surface area (TSA) = 3Ï€r |

## Surface area of Hemisphere Formula Examples

**Question**: The radius of a red balloon increases from 6cm to 12 cm when the air is pumped into it. Calculate the ratios of the surface areas of the balloon in both the cases.

**Solution**: Hemisphere 1 – r = 6cm

Hemisphere 2 – r = 12 cm

TSA – 1 = 3Ï€r^{2}

= 3Ï€(6)^{2}

TSA – 2 =3Ï€(12)^{2}

Letâ€™s find the ratio: TSA_{1 }/TSA_{2,} = Â½

To find the other Mathematical formulas with practice examples, register at BYJUâ€™S.