Finding the Fourth Proportional to 39,903.48, 55,067.18 and 21,999.12

Step by Step Solution

1. Step 1: Write the proportion equation
   39,903.48 : 55,067.18 = 21,999.12 : x
2. Step 2: Convert to fraction form
   39,903.48/55,067.18 = 21,999.12/x
3. Step 3: Cross multiply
   39,903.48x = 55,067.18 × 21,999.12
4. Step 4: Simplify right side
   39,903.48x = 1,211,429,390.89
5. Step 5: Solve for x
   x = 1,211,429,390.89/39,903.48
6. Step 6: Final answer
   x = 30,358.99