Finding the Fourth Proportional to 39,902.31, 55,064.88 and 21,998.07

Step by Step Solution

1. Step 1: Write the proportion equation
   39,902.31 : 55,064.88 = 21,998.07 : x
2. Step 2: Convert to fraction form
   39,902.31/55,064.88 = 21,998.07/x
3. Step 3: Cross multiply
   39,902.31x = 55,064.88 × 21,998.07
4. Step 4: Simplify right side
   39,902.31x = 1,211,321,084.78
5. Step 5: Solve for x
   x = 1,211,321,084.78/39,902.31
6. Step 6: Final answer
   x = 30,357.17