<span>A method of processing coal to remove contaminants by mixing coal in a solution of potassium permanganate in a selected concentration range, rinsing the coal, mixing the coal in a solution of ammonia hydroxide in a selected concentration range to cause the solution to be brought into contact with the surfaces and pores of the coal, discharging the processed coal from the second reaction vessel, monitoring the process to detect when the concentration of aqueous ammonia in the second reaction vessel has fallen below the selected range, and feeding aqueous ammonia solution with an ammonia concentration in or above the selected range to the second reaction vessel to return the solution to within the selected range.</span>
Answer: 
Explanation:
We have a right triangle with sides AB, BC=5cm and AC=13cm (the hypotenuse). Let's apply the Pithagorean Theorem to find AB:
(1)
(2)
(3)
(4)
Now that we know the value of each side of the triangle, we will use the trigonometric function sine to find the angles C and A (angle B is 
remembering we are talking about a right triangle):
For angle C:
(5)
(6)
(7)
For angle A:
(8)
(9)
(10)
Calculating the difference between both angles:
A. The spelling of the two words might be similar and some sounds might be the same.
Although it is possible for words in two different languages to have the same spelling and/or pronunciation, it is much more likely that they would be similar. Since, the languages are derived from the same root and belong to the same family, it would make sense that the words would be similar, if not exactly the same.
