Finding the Third Proportional to 86,691 and 128,713.50

Step by Step Solution

1. Step 1: Write the proportion equation
   86,691 : 128,713.50 = 128,713.50 : x
2. Step 2: Convert to fraction form
   86,691/128,713.50 = 128,713.50/x
3. Step 3: Cross multiply
   86,691x = 128,713.50 × 128,713.50
4. Step 4: Simplify right side
   86,691x = 16,567,165,082.25
5. Step 5: Solve for x
   x = 16,567,165,082.25/86,691
6. Step 6: Final answer
   x = 191,105.94