Aḥessb i uḥess n iberdan i usnulfu n uqeclaw
R1 - Radius n daxel n tqacuct.
R2 - Radius n berra n arc.
S - Amḍan n yiferdisen n tmeẓẓuɣt.
U - Angle n yiwen n ugzum n yiwen n uswir.
Tizemmar n wahil.
Leḥsab n tɣawsiwin d umḍan n yiferdisen i lmend n usnulfu n tmeẓdiyin n useklu.