Finding the Fourth Proportional to 21,152.96, 31,694.83 and 12,807.70

Step by Step Solution

1. Step 1: Write the proportion equation
   21,152.96 : 31,694.83 = 12,807.70 : x
2. Step 2: Convert to fraction form
   21,152.96/31,694.83 = 12,807.70/x
3. Step 3: Cross multiply
   21,152.96x = 31,694.83 × 12,807.70
4. Step 4: Simplify right side
   21,152.96x = 405,937,762.93
5. Step 5: Solve for x
   x = 405,937,762.93/21,152.96
6. Step 6: Final answer
   x = 19,190.59