What are Ratios? - Definition & Examples

What is the ratio of the number of triangles, $\triangle$, to the number of circles, $\circ$?

$\triangle\triangle\triangle\circ\circ\circ\circ\circ\circ\\ \triangle\triangle\triangle\circ\circ\circ\circ\circ\circ\\ \triangle\triangle\triangle\circ\circ\circ\circ\circ\circ$