(1) circle * triangle =300, (2) square * triangle = 15, (3) square * circle = 180. These are three known conditions.

(3)÷(2) A circle is a multiple of a triangle 180÷ 15= 12.

(1) multiplication is a triangle multiplied by a triangle 300÷ 12=25 25=5×5. The triangle is 5.

A circle with 300÷5=60 is 60 180÷60=3 and a square is 3.