Solution: We are given below data:

Now to find the mean deviation, we use the below formula:

Where:
represents the summation
X, represents the observation.
represents the mean
N represents the number of observation.


Therefore, the mean deviation is:

= 4
Cosine(angle) = adjacent leg/ hypotenuse
Cosine( angle ) = 18/20
Angle = arccos(18/20)
Angle = 26 degrees
Lets check...
42/56 = 56/64
cross multiply
(56)(56) = (42)(64)
3136 = 2688...(incorrect)...these are not proportional
proportions are nothing but equivalent fractions
42/56 = 3/4
56/64 = 7/8
as u can see, they are not equivalent fractions...so they are not proportional
Based on the given figure above, the correct answer would be option A. Judging by appearance, the figure can be classified by the following: <span>rectangle, square, quadrilateral, parallelogram, and rhombus. It cannot be classified as a rectangle nor as a trapezoid. Hope this answers your question. </span>
18* is 18 above 0. -12* is 12 below 0.
So add: 18+12=X. The difference in temperature is X :)