Why-does-the-energy-of-a-sound-wave -decrease-over-time

What is the length x of the side of the triangle below? (hint: use the cosine function)

Abag of potato chips contains 2.00 l of air when it is sealed at sea level at a pressure of 1.00 atm and a temperature of 20.0 deg c. what will be the volume of the air in the bag if you take it with you, still sealed, to the mountains where the temperature is 7.00 deg c and atmospheric pressure is 70.0 kpa? assume that the bag behaves like a balloon and that the air in the bag is in thermal equilibrium with the outside air.

Which lists the amplitudes of sound waves from these sources in order from greatest to least? busy roadway, kids whispering, average home chainsaw, diesel truck, rustling leaves kids whispering, vacuum cleaner, jet airplane library, conversational speech, music from speaker