draw a right triangle in quadrant I
you know the hypotenuse and the opposite side but not the adjacent side
use the Pythagorean Theorem
(√13)2=22+a2 where a=adjacent side
point: P=(3,2) for the value of sin that is given, which is one of infinitely many points if the sides of the triangle are all extended (doubled, tripled,...), or shortened (1/2 each side, 1/4 each side,...)
other points are P=(6,4), P=(9,6), ...