Finding the Fourth Proportional to 51,439.31, 70,985.89 and 28,778.21

Step by Step Solution

1. Step 1: Write the proportion equation
   51,439.31 : 70,985.89 = 28,778.21 : x
2. Step 2: Convert to fraction form
   51,439.31/70,985.89 = 28,778.21/x
3. Step 3: Cross multiply
   51,439.31x = 70,985.89 × 28,778.21
4. Step 4: Simplify right side
   51,439.31x = 2,042,846,849.46
5. Step 5: Solve for x
   x = 2,042,846,849.46/51,439.31
6. Step 6: Final answer
   x = 39,713.73