Finding the Third Proportional to 291,249 and 391,128.75

Step by Step Solution

1. Step 1: Write the proportion equation
   291,249 : 391,128.75 = 391,128.75 : x
2. Step 2: Convert to fraction form
   291,249/391,128.75 = 391,128.75/x
3. Step 3: Cross multiply
   291,249x = 391,128.75 × 391,128.75
4. Step 4: Simplify right side
   291,249x = 152,981,699,076.56
5. Step 5: Solve for x
   x = 152,981,699,076.56/291,249
6. Step 6: Final answer
   x = 525,260.86