Finding the Third Proportional to 420,112 and 645,742.50

Step by Step Solution

1. Step 1: Write the proportion equation
   420,112 : 645,742.50 = 645,742.50 : x
2. Step 2: Convert to fraction form
   420,112/645,742.50 = 645,742.50/x
3. Step 3: Cross multiply
   420,112x = 645,742.50 × 645,742.50
4. Step 4: Simplify right side
   420,112x = 416,983,376,306.25
5. Step 5: Solve for x
   x = 416,983,376,306.25/420,112
6. Step 6: Final answer
   x = 992,552.88