Finding the Third Proportional to 642,421 and 903,870.50

Step by Step Solution

1. Step 1: Write the proportion equation
   642,421 : 903,870.50 = 903,870.50 : x
2. Step 2: Convert to fraction form
   642,421/903,870.50 = 903,870.50/x
3. Step 3: Cross multiply
   642,421x = 903,870.50 × 903,870.50
4. Step 4: Simplify right side
   642,421x = 816,981,880,770.25
5. Step 5: Solve for x
   x = 816,981,880,770.25/642,421
6. Step 6: Final answer
   x = 1,271,723.50