Finding the Fourth Proportional to 21,138.83, 31,685.36 and 13,748.59

Step by Step Solution

1. Step 1: Write the proportion equation
   21,138.83 : 31,685.36 = 13,748.59 : x
2. Step 2: Convert to fraction form
   21,138.83/31,685.36 = 13,748.59/x
3. Step 3: Cross multiply
   21,138.83x = 31,685.36 × 13,748.59
4. Step 4: Simplify right side
   21,138.83x = 435,628,875.69
5. Step 5: Solve for x
   x = 435,628,875.69/21,138.83
6. Step 6: Final answer
   x = 20,608.00