Finding the Fourth Proportional to 12,986.84, 17,917.61 and 7,945.80

Step by Step Solution

1. Step 1: Write the proportion equation
   12,986.84 : 17,917.61 = 7,945.80 : x
2. Step 2: Convert to fraction form
   12,986.84/17,917.61 = 7,945.80/x
3. Step 3: Cross multiply
   12,986.84x = 17,917.61 × 7,945.80
4. Step 4: Simplify right side
   12,986.84x = 142,369,765.40
5. Step 5: Solve for x
   x = 142,369,765.40/12,986.84
6. Step 6: Final answer
   x = 10,962.62