Finding the Third Proportional to 312,121.50 and 663,123

Step by Step Solution

1. Step 1: Write the proportion equation
   312,121.50 : 663,123 = 663,123 : x
2. Step 2: Convert to fraction form
   312,121.50/663,123 = 663,123/x
3. Step 3: Cross multiply
   312,121.50x = 663,123 × 663,123
4. Step 4: Simplify right side
   312,121.50x = 439,732,113,129
5. Step 5: Solve for x
   x = 439,732,113,129/312,121.50
6. Step 6: Final answer
   x = 1,408,849.16