Finding the Third Proportional to 420,375 and 640,282.50

Step by Step Solution

1. Step 1: Write the proportion equation
   420,375 : 640,282.50 = 640,282.50 : x
2. Step 2: Convert to fraction form
   420,375/640,282.50 = 640,282.50/x
3. Step 3: Cross multiply
   420,375x = 640,282.50 × 640,282.50
4. Step 4: Simplify right side
   420,375x = 409,961,679,806.25
5. Step 5: Solve for x
   x = 409,961,679,806.25/420,375
6. Step 6: Final answer
   x = 975,228.50