Finding the Fourth Proportional to 12,978.39, 19,466.76 and 5,181.60

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.39 : 19,466.76 = 5,181.60 : x
2. Step 2: Convert to fraction form
   12,978.39/19,466.76 = 5,181.60/x
3. Step 3: Cross multiply
   12,978.39x = 19,466.76 × 5,181.60
4. Step 4: Simplify right side
   12,978.39x = 100,868,963.62
5. Step 5: Solve for x
   x = 100,868,963.62/12,978.39
6. Step 6: Final answer
   x = 7,772.07