Finding the Third Proportional to 291,139.50 and 636,255

Step by Step Solution

1. Step 1: Write the proportion equation
   291,139.50 : 636,255 = 636,255 : x
2. Step 2: Convert to fraction form
   291,139.50/636,255 = 636,255/x
3. Step 3: Cross multiply
   291,139.50x = 636,255 × 636,255
4. Step 4: Simplify right side
   291,139.50x = 404,820,425,025
5. Step 5: Solve for x
   x = 404,820,425,025/291,139.50
6. Step 6: Final answer
   x = 1,390,468.92