143 is composite. To be prime it has to have only 2 divisors i.e it's self and one but since it has 4 divisors ( 143, 1, 11 and 13) it is composite.
(a) SSS (side side side)
every side on one triangle is correspondingly equal to that of the same side in the other triangle
A cord: and the longest cord in a circle is the diameter , so a diameter is a special case of cord.