Finding the Third Proportional to 420,120 and 645,754.50

Step by Step Solution

1. Step 1: Write the proportion equation
   420,120 : 645,754.50 = 645,754.50 : x
2. Step 2: Convert to fraction form
   420,120/645,754.50 = 645,754.50/x
3. Step 3: Cross multiply
   420,120x = 645,754.50 × 645,754.50
4. Step 4: Simplify right side
   420,120x = 416,998,874,270.25
5. Step 5: Solve for x
   x = 416,998,874,270.25/420,120
6. Step 6: Final answer
   x = 992,570.87