Finding the Fourth Proportional to 100,498.50, 138,689.55 and 55,786.50

Step by Step Solution

1. Step 1: Write the proportion equation
   100,498.50 : 138,689.55 = 55,786.50 : x
2. Step 2: Convert to fraction form
   100,498.50/138,689.55 = 55,786.50/x
3. Step 3: Cross multiply
   100,498.50x = 138,689.55 × 55,786.50
4. Step 4: Simplify right side
   100,498.50x = 7,737,004,581.08
5. Step 5: Solve for x
   x = 7,737,004,581.08/100,498.50
6. Step 6: Final answer
   x = 76,986.27