Checking Kepler's Third Law

(You'll need to view this in landscape mode if using a small screen).

For Earth and the inner planets:

Planet	Orbit radius (r) in AUs	r^3	Period (t) in years	t^2	r^3/t^2
Mercury	sin 22.5° *	~0.06	7/29	0.06	0.96
Venus	sin 46° *	~0.37	8/13	0.38	0.98
Earth	1	1	1	1	1

(*approximate average greatest elongation from data here)

So far, so good, but to extend this to the outer planets, I'll need a method of determining the orbital radii for those. 🤔