You can see the masts at Anthorn from our back garden. They are as tall as my little finger's width when I hold it at arm's length. That means that they subtend 1 degree. In radians that is 0.017 rad. Using radians I can model the height of the mast as an arc length. Angle in radians = arc length/radius. In this case the radius means the distance to the masts, which are about 10 miles from here or 16 km. That means the height of the masts is 16000 x 0.017 = 280 metres.
https://en.wikipedia.org/wiki/Anthorn_Radio_Station gives the mast height as 228 metres so that's not bad!
