Finding the Third Proportional to 291,258 and 391,142.25

Step by Step Solution

1. Step 1: Write the proportion equation
   291,258 : 391,142.25 = 391,142.25 : x
2. Step 2: Convert to fraction form
   291,258/391,142.25 = 391,142.25/x
3. Step 3: Cross multiply
   291,258x = 391,142.25 × 391,142.25
4. Step 4: Simplify right side
   291,258x = 152,992,259,735.06
5. Step 5: Solve for x
   x = 152,992,259,735.06/291,258
6. Step 6: Final answer
   x = 525,280.88