Finding the Fourth Proportional to 12,687.84, 19,003.55 and 8,978.85

Step by Step Solution

1. Step 1: Write the proportion equation
   12,687.84 : 19,003.55 = 8,978.85 : x
2. Step 2: Convert to fraction form
   12,687.84/19,003.55 = 8,978.85/x
3. Step 3: Cross multiply
   12,687.84x = 19,003.55 × 8,978.85
4. Step 4: Simplify right side
   12,687.84x = 170,629,980.02
5. Step 5: Solve for x
   x = 170,629,980.02/12,687.84
6. Step 6: Final answer
   x = 13,448.31