Finding the Fourth Proportional to 21,932.28, 30,264.30 and 12,978.06

Step by Step Solution

1. Step 1: Write the proportion equation
   21,932.28 : 30,264.30 = 12,978.06 : x
2. Step 2: Convert to fraction form
   21,932.28/30,264.30 = 12,978.06/x
3. Step 3: Cross multiply
   21,932.28x = 30,264.30 × 12,978.06
4. Step 4: Simplify right side
   21,932.28x = 392,771,901.26
5. Step 5: Solve for x
   x = 392,771,901.26/21,932.28
6. Step 6: Final answer
   x = 17,908.39