Finding the Fourth Proportional to 39,885.62, 55,039.91 and 21,980.57

Step by Step Solution

1. Step 1: Write the proportion equation
   39,885.62 : 55,039.91 = 21,980.57 : x
2. Step 2: Convert to fraction form
   39,885.62/55,039.91 = 21,980.57/x
3. Step 3: Cross multiply
   39,885.62x = 55,039.91 × 21,980.57
4. Step 4: Simplify right side
   39,885.62x = 1,209,808,209.45
5. Step 5: Solve for x
   x = 1,209,808,209.45/39,885.62
6. Step 6: Final answer
   x = 30,331.94