Finding the Fourth Proportional to 39,780.59, 54,895.79 and 21,875.47

Step by Step Solution

1. Step 1: Write the proportion equation
   39,780.59 : 54,895.79 = 21,875.47 : x
2. Step 2: Convert to fraction form
   39,780.59/54,895.79 = 21,875.47/x
3. Step 3: Cross multiply
   39,780.59x = 54,895.79 × 21,875.47
4. Step 4: Simplify right side
   39,780.59x = 1,200,871,124.72
5. Step 5: Solve for x
   x = 1,200,871,124.72/39,780.59
6. Step 6: Final answer
   x = 30,187.37