Which of the following would a person interested in thermodynamics study a. solar energy b. water puirfication c. combating cancer d. governing systems

B water purification

Step-by-step explanation:

Water purification is a thermodynamics process that involves Boiling. The simplest and most common method to purify drinking water is to boil it. Heat the water over a stove top burner or open flame until it reaches a full, rolling boil, and continue to boil for a minimum of five to ten minutes to be safe (the longer the water is boiled, the purer it will become).

answer:  

step-by-step explanation:

here x represents the height of the pole,

and, the height of the shadow of the pole is 12 feet.

also, the angle of elevation from the top of the pole is 40°,

therefore,

by the low of sine,

which is the required equation for finding the value of x,