Take any equilateral triangle $ABD$, then extend the side $AB$ into a line. Take a point $C\in \overleftrightarrow{AB}$, and trace the line $\overleftrightarrow{CD}$. Circles $G$ and $E$ are both tangent to the equilateral triangle, and to the lines $\overleftrightarrow{AB}$ and $\overleftrightarrow{AD}$. Prove that the height of the triangle $ABD$ equals the sume of the radii of the circles $G$ and $E$, regardless the position of point $C$ in the line $\overleftrightarrow{AB}$. Here's an image with some other elements:

Note: Dotted lines in the image represent angle bisectors of the angles they cut through. It's easy to show that the centers of the circles must lie on those angle bisectors. $M$ is the mid-point of side $AB$. Some tangency points, such as $I$ and $J$ have also been marked.

$$\left.\begin{align} p+r &= 2t \\ q+s &= 2t \\ p+q &= 2t + r + s \end{align} \quad \right\rbrace \implies \quad t = r + s$$