The single-span suspension bridge crossing the estuary of the Humber River on the east coast of England has towers that are 162.5 meters tall (AC=BD). The span at sea level is 1410 meters (about 4/5 of a mile). The tops of the towers are 3.6 cm farther apart than the bases (i.e. AB=1410.036 m). What is the radius of the earth?

So the radius of the earth is *x* meters.

Since the earth is not a perfect sphere, its radius varies between 6357 km to 6378 km. Sou our 6365 km is reasonable.

(One could find the exact radius at the bridge and then work backwards to find a more exact measurement between the tops of the towers.)