Finding the Fourth Proportional to 39,780.30, 54,896.94 and 21,876.42

Step by Step Solution

1. Step 1: Write the proportion equation
   39,780.30 : 54,896.94 = 21,876.42 : x
2. Step 2: Convert to fraction form
   39,780.30/54,896.94 = 21,876.42/x
3. Step 3: Cross multiply
   39,780.30x = 54,896.94 × 21,876.42
4. Step 4: Simplify right side
   39,780.30x = 1,200,948,516.15
5. Step 5: Solve for x
   x = 1,200,948,516.15/39,780.30
6. Step 6: Final answer
   x = 30,189.53