Finding the Fourth Proportional to 13,978.78, 20,964.64 and 8,358.06

Step by Step Solution

1. Step 1: Write the proportion equation
   13,978.78 : 20,964.64 = 8,358.06 : x
2. Step 2: Convert to fraction form
   13,978.78/20,964.64 = 8,358.06/x
3. Step 3: Cross multiply
   13,978.78x = 20,964.64 × 8,358.06
4. Step 4: Simplify right side
   13,978.78x = 175,223,719.00
5. Step 5: Solve for x
   x = 175,223,719.00/13,978.78
6. Step 6: Final answer
   x = 12,534.98