Finding the Third Proportional to 212,838 and 318,671.25

Step by Step Solution

1. Step 1: Write the proportion equation
   212,838 : 318,671.25 = 318,671.25 : x
2. Step 2: Convert to fraction form
   212,838/318,671.25 = 318,671.25/x
3. Step 3: Cross multiply
   212,838x = 318,671.25 × 318,671.25
4. Step 4: Simplify right side
   212,838x = 101,551,365,576.56
5. Step 5: Solve for x
   x = 101,551,365,576.56/212,838
6. Step 6: Final answer
   x = 477,129.86