Finding the Third Proportional to 423,861 and 640,111.50

Step by Step Solution

1. Step 1: Write the proportion equation
   423,861 : 640,111.50 = 640,111.50 : x
2. Step 2: Convert to fraction form
   423,861/640,111.50 = 640,111.50/x
3. Step 3: Cross multiply
   423,861x = 640,111.50 × 640,111.50
4. Step 4: Simplify right side
   423,861x = 409,742,732,432.25
5. Step 5: Solve for x
   x = 409,742,732,432.25/423,861
6. Step 6: Final answer
   x = 966,691.28