Finding the Fourth Proportional to 21,128.76, 31,670.35 and 13,738.52

Step by Step Solution

1. Step 1: Write the proportion equation
   21,128.76 : 31,670.35 = 13,738.52 : x
2. Step 2: Convert to fraction form
   21,128.76/31,670.35 = 13,738.52/x
3. Step 3: Cross multiply
   21,128.76x = 31,670.35 × 13,738.52
4. Step 4: Simplify right side
   21,128.76x = 435,103,736.88
5. Step 5: Solve for x
   x = 435,103,736.88/21,128.76
6. Step 6: Final answer
   x = 20,592.96