Finding the Fourth Proportional to 12,991.94, 17,929.05 and 7,686.62

Step by Step Solution

1. Step 1: Write the proportion equation
   12,991.94 : 17,929.05 = 7,686.62 : x
2. Step 2: Convert to fraction form
   12,991.94/17,929.05 = 7,686.62/x
3. Step 3: Cross multiply
   12,991.94x = 17,929.05 × 7,686.62
4. Step 4: Simplify right side
   12,991.94x = 137,813,794.31
5. Step 5: Solve for x
   x = 137,813,794.31/12,991.94
6. Step 6: Final answer
   x = 10,607.64