Finding the Third Proportional to 129,816 and 257,782.50

Step by Step Solution

1. Step 1: Write the proportion equation
   129,816 : 257,782.50 = 257,782.50 : x
2. Step 2: Convert to fraction form
   129,816/257,782.50 = 257,782.50/x
3. Step 3: Cross multiply
   129,816x = 257,782.50 × 257,782.50
4. Step 4: Simplify right side
   129,816x = 66,451,817,306.25
5. Step 5: Solve for x
   x = 66,451,817,306.25/129,816
6. Step 6: Final answer
   x = 511,892.35