Finding the Fourth Proportional to 31,406.50, 47,131.35 and 12,938.50

Step by Step Solution

1. Step 1: Write the proportion equation
   31,406.50 : 47,131.35 = 12,938.50 : x
2. Step 2: Convert to fraction form
   31,406.50/47,131.35 = 12,938.50/x
3. Step 3: Cross multiply
   31,406.50x = 47,131.35 × 12,938.50
4. Step 4: Simplify right side
   31,406.50x = 609,808,971.98
5. Step 5: Solve for x
   x = 609,808,971.98/31,406.50
6. Step 6: Final answer
   x = 19,416.65