Finding the Third Proportional to 420,002.72 and 645,939.56

Step by Step Solution

1. Step 1: Write the proportion equation
   420,002.72 : 645,939.56 = 645,939.56 : x
2. Step 2: Convert to fraction form
   420,002.72/645,939.56 = 645,939.56/x
3. Step 3: Cross multiply
   420,002.72x = 645,939.56 × 645,939.56
4. Step 4: Simplify right side
   420,002.72x = 417,237,918,402.69
5. Step 5: Solve for x
   x = 417,237,918,402.69/420,002.72
6. Step 6: Final answer
   x = 993,417.18