Finding the Third Proportional to 57,139.50 and 85,654.50

Step by Step Solution

1. Step 1: Write the proportion equation
   57,139.50 : 85,654.50 = 85,654.50 : x
2. Step 2: Convert to fraction form
   57,139.50/85,654.50 = 85,654.50/x
3. Step 3: Cross multiply
   57,139.50x = 85,654.50 × 85,654.50
4. Step 4: Simplify right side
   57,139.50x = 7,336,693,370.25
5. Step 5: Solve for x
   x = 7,336,693,370.25/57,139.50
6. Step 6: Final answer
   x = 128,399.68