When the average daily temperature in New York City decreases, the number of persons who are observed wearing sweaters in the workplace increases, this implies a<u> </u><u>negative correlation.</u>
Negative correlation simply means the relationship between two variables where as one variable increases, the other variable will reduce.
Therefore, in a situation where the average daily temperature in New York City decreases and the number of persons who are observed wearing sweaters in the workplace increases, this illustrates a negative correlation.
Drawing this square and then drawing in the four radii from the center of the cirble to each of the vertices of the square results in the construction of four triangular areas whose hypotenuse is 3 sqrt(2). Draw this to verify this statement. Note that the height of each such triangular area is (3 sqrt(2))/2.
So now we have the base and height of one of the triangular sections.
The area of a triangle is A = (1/2) (base) (height). Subst. the values discussed above, A = (1/2) (3 sqrt(2) ) (3/2) sqrt(2). Show that this boils down to A = 9/2.
You could also use the fact that the area of a square is (length of one side)^2, and then take (1/4) of this area to obtain the area of ONE triangular section. Doing the problem this way, we get (1/4) (3 sqrt(2) )^2. Thus, A = (1/4) (9 * 2) = (9/2). Same answer as before.