Finding the Third Proportional to 128,154.50 and 296,680

Step by Step Solution

1. Step 1: Write the proportion equation
   128,154.50 : 296,680 = 296,680 : x
2. Step 2: Convert to fraction form
   128,154.50/296,680 = 296,680/x
3. Step 3: Cross multiply
   128,154.50x = 296,680 × 296,680
4. Step 4: Simplify right side
   128,154.50x = 88,019,022,400
5. Step 5: Solve for x
   x = 88,019,022,400/128,154.50
6. Step 6: Final answer
   x = 686,819.60