Finding the Third Proportional to 521,131.50 and 781,699.50

Step by Step Solution

1. Step 1: Write the proportion equation
   521,131.50 : 781,699.50 = 781,699.50 : x
2. Step 2: Convert to fraction form
   521,131.50/781,699.50 = 781,699.50/x
3. Step 3: Cross multiply
   521,131.50x = 781,699.50 × 781,699.50
4. Step 4: Simplify right side
   521,131.50x = 611,054,108,300.25
5. Step 5: Solve for x
   x = 611,054,108,300.25/521,131.50
6. Step 6: Final answer
   x = 1,172,552.63