Question

A cloud directly above you is about 10° across. From the weather report you know that the cloud is at an altitude of 2200 m. How wide is the cloud?

Answer 1

2 π Θ = 360 where Θ is the angle of 1 rad = 57.3 deg

W = R Θ = 2200 m * 10 / 57.3 = 384 m

Note: The difference between radian measure (distance along arc of circle) and the chord of a circle is quite small for 10 deg - probably the cloud is not completely flat anyway