Finding the Fourth Proportional to 31,099.89, 42,935.03 and 21,915.86

Step by Step Solution

1. Step 1: Write the proportion equation
   31,099.89 : 42,935.03 = 21,915.86 : x
2. Step 2: Convert to fraction form
   31,099.89/42,935.03 = 21,915.86/x
3. Step 3: Cross multiply
   31,099.89x = 42,935.03 × 21,915.86
4. Step 4: Simplify right side
   31,099.89x = 940,957,946.69
5. Step 5: Solve for x
   x = 940,957,946.69/31,099.89
6. Step 6: Final answer
   x = 30,255.99