The circumference of a circle is (2π · the circle's radius).
The length of a semi-circle is (1π · the circle's radius) =
(π · 14.8) = 46.5 (rounded)
(The unit is the same as whatever the unit of the 14.8 is.)
nuclear fusion- produces huge amounts of energy.
The time for the echo to return is directly proportional to the distance. vw = fλ. In a given medium under fixed conditions, vw is constant, so that there is a relationship between f and λ; the higher the frequency, the smaller the wavelength.