<prompt> The effective diameter of the tympanic membrane:25 mm230 mm240 mm245 mm2  <response>: Area of tympanic membrane is 90 mm2.Effective area is 55 mrn2approximately 23 of the total area.Significance of large area of tympanic membrane - The area of tympanic is much larger than area of stapes footplate, which helps in conveing sound of greater amplitude but lesser force to that of lesser amplitude and great force. 