This exercize is divided into two main parts. The first one intends to give a clear idea about the UV coverage with baselines of different orientations and targets of different declinations. It also emphasizes on the delay lines constraints for a 2 and a 3-telescope array. In the second part, different array configurations have to be selected to efficiently measure the radius of 3 close M dwarfs and the parameters (ρ, Θ, Δmag) of a binary system.