The height of a transverse wave from the midpoint to the crest or trough is the .

From the midpoint to the crest or trough, the height of a transverse wave is known as amplitude.

Explanation:

The crest’s or trough’s midpoint in the transverse wave are amplitudes in the height. The transverse waves which propagate to the perpendicular of the line in it. The waves have three features, namely, frequency, amplitude and wavelength.

Amplitude defines as the vertical height from the equilibrium line or position in the mid-point of the wave formation. There are two formation in transverse waves which are crest and trough.  

305.7

explanation:

density =m/v

density =917/3.00

density = 305.

approximately = 305.7

in four significant figures