In a function, each domain element can have at most one range element. So we'll have to remove one of the links from 3. Either one can be removed, since it is OK for two domain elements to map to the same range element (as is the case for 3->b and 4->b).
This is all very theoretical, but here is a real life example.
Take f(x) = x²
You probably know that both f(2) and f(-2) is 4.
There 2 and -2 are in the domain, 4 is in the range.
Answer: The height is 6.07 meters
Step-by-step Explanation: The distance between the elevator and the bottom of the barn is given as 9 meters. Also for the hay elevator to move bales of hay to the second story of the barn lift it makes an angle of elevation of 34 degrees with the ground. With these we can derive a right angled triangle with the reference angle as 34 degrees, the side facing it which is the height or h (opposite) is yet unknown, and the side between the reference angle and the right angle (adjacent) is 9. We shall apply the trigonometric ratio as follows;
Tan 34 = opposite/adjacent
Tan 34 = h/9
0.6745 = h/9
0.6745 x 9 = h
6.0705 = h
Therefore the approximate height of the barn to the ground is 6.07 meters
(Unless the rectangle is a square.) And the angles formed by the intersection are not always the same measure (size). Opposite central angles are the same size (they are congruent.)