  This paper focuses on securing a triangular shape (up to translation) for a
team of three mobile robots that uses heterogeneous sensing mechanism. Based on
the available local information, each robot employs the popular gradient-based
control law to attain the assigned individual task(s). In the current work,
robots are assigned either distance and signed area task(s) or bearing task(s).
We provide a sufficient condition on the gain ratio $R_{\text{Ad}}$ between the
signed area and the distance control term such that the desired formation
shape, an isosceles triangle, is reached from all feasible starting positions.
Numerical simulations are provided to support the theoretical analyses.
