Let x = 6.2
Define y as half of x: y = 0.5x
Calculate y: y = 0.5 × 6.2 = 3.1
Calculate z by subtracting x and y from 14.5: z = 14.5 - 6.2 - 3.1 = 5.2
Each variable corresponds to a triangle side
A proportion maintains a consistent ratio m/d
If m = 0.75d, then the m/d ratio translates to (0.75d)/d = 0.75
In this case, the ratio can be expressed as (.75d-2)/d = 0.75 - (2/d).
Thus, it is not proportional.
Answer:
The original cost amounts to $10
Step-by-step explanation:
Let us denote the cost as x
where Price = x + (0.5x) = 1.50x
Now, the price after reduction is 20% of 1.50x
which is 0.3x 
This leads to the equation 1.50x - 0.3x = 12
resulting in 1.2x = 12
which gives us x = 10
thus, the cost is $10