Finding the Fourth Proportional to 100,140.50, 138,196.06 and 55,428.50

Step by Step Solution

1. Step 1: Write the proportion equation
   100,140.50 : 138,196.06 = 55,428.50 : x
2. Step 2: Convert to fraction form
   100,140.50/138,196.06 = 55,428.50/x
3. Step 3: Cross multiply
   100,140.50x = 138,196.06 × 55,428.50
4. Step 4: Simplify right side
   100,140.50x = 7,660,000,311.71
5. Step 5: Solve for x
   x = 7,660,000,311.71/100,140.50
6. Step 6: Final answer
   x = 76,492.53