Finding the Fourth Proportional to 39,897.78, 55,056.76 and 21,991.38

Step by Step Solution

1. Step 1: Write the proportion equation
   39,897.78 : 55,056.76 = 21,991.38 : x
2. Step 2: Convert to fraction form
   39,897.78/55,056.76 = 21,991.38/x
3. Step 3: Cross multiply
   39,897.78x = 55,056.76 × 21,991.38
4. Step 4: Simplify right side
   39,897.78x = 1,210,773,855.45
5. Step 5: Solve for x
   x = 1,210,773,855.45/39,897.78
6. Step 6: Final answer
   x = 30,346.90