Finding the Fourth Proportional to 105,427.80, 145,490.72 and 57,681

Step by Step Solution

1. Step 1: Write the proportion equation
   105,427.80 : 145,490.72 = 57,681 : x
2. Step 2: Convert to fraction form
   105,427.80/145,490.72 = 57,681/x
3. Step 3: Cross multiply
   105,427.80x = 145,490.72 × 57,681
4. Step 4: Simplify right side
   105,427.80x = 8,392,049,931.92
5. Step 5: Solve for x
   x = 8,392,049,931.92/105,427.80
6. Step 6: Final answer
   x = 79,599.97