What is the shape of the 'dish' of a dish antenna used for receiving TV signals from a satellite ?

The diagram shows a dish antenna which is used to receive televisiton signals form a satellite. The antenna (signal detector ) is fixed forn of the curved dish .

Antennas are used to receive and transmit

find the minimum colatitude which can directly receive a signal from a geostationary satellite.

What type of detergents are used for dish washing ?

A transmitting antenna of height 25 m is fitted at the top of a tower of height 20m. What is the height of the receiving antenna from ground level if the maximum distance between transmitting antenna and receiving antenna on ground is 56 km. Radius of earth = 6400 km.

Two identical antennas mounted on identical towers are separated from each other by a distance of 45 km. What should nearly be the minimum height of receiving antenna to receive the signals in line of sight? (Assume radius of earth is 6400 km)