Finding the Fourth Proportional to 78,128.76, 107,817.71 and 42,318.66

Step by Step Solution

1. Step 1: Write the proportion equation
   78,128.76 : 107,817.71 = 42,318.66 : x
2. Step 2: Convert to fraction form
   78,128.76/107,817.71 = 42,318.66/x
3. Step 3: Cross multiply
   78,128.76x = 107,817.71 × 42,318.66
4. Step 4: Simplify right side
   78,128.76x = 4,562,701,011.47
5. Step 5: Solve for x
   x = 4,562,701,011.47/78,128.76
6. Step 6: Final answer
   x = 58,399.76