Finding the Fourth Proportional to 21,305,315.30, 31,939,310.55 and 12,789,040.10

Step by Step Solution

1. Step 1: Write the proportion equation
   21,305,315.30 : 31,939,310.55 = 12,789,040.10 : x
2. Step 2: Convert to fraction form
   21,305,315.30/31,939,310.55 = 12,789,040.10/x
3. Step 3: Cross multiply
   21,305,315.30x = 31,939,310.55 × 12,789,040.10
4. Step 4: Simplify right side
   21,305,315.30x = 408,473,123,390,303.06
5. Step 5: Solve for x
   x = 408,473,123,390,303.06/21,305,315.30
6. Step 6: Final answer
   x = 19,172,357.58