Finding the Fourth Proportional to 12,978.54, 19,465.98 and 4,213.56

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.54 : 19,465.98 = 4,213.56 : x
2. Step 2: Convert to fraction form
   12,978.54/19,465.98 = 4,213.56/x
3. Step 3: Cross multiply
   12,978.54x = 19,465.98 × 4,213.56
4. Step 4: Simplify right side
   12,978.54x = 82,021,074.69
5. Step 5: Solve for x
   x = 82,021,074.69/12,978.54
6. Step 6: Final answer
   x = 6,319.75