Finding the Third Proportional to 420,138 and 630,517.50

Step by Step Solution

1. Step 1: Write the proportion equation
   420,138 : 630,517.50 = 630,517.50 : x
2. Step 2: Convert to fraction form
   420,138/630,517.50 = 630,517.50/x
3. Step 3: Cross multiply
   420,138x = 630,517.50 × 630,517.50
4. Step 4: Simplify right side
   420,138x = 397,552,317,806.25
5. Step 5: Solve for x
   x = 397,552,317,806.25/420,138
6. Step 6: Final answer
   x = 946,242.23