Finding the Third Proportional to 390,118.50 and 851,679

Step by Step Solution

1. Step 1: Write the proportion equation
   390,118.50 : 851,679 = 851,679 : x
2. Step 2: Convert to fraction form
   390,118.50/851,679 = 851,679/x
3. Step 3: Cross multiply
   390,118.50x = 851,679 × 851,679
4. Step 4: Simplify right side
   390,118.50x = 725,357,119,041
5. Step 5: Solve for x
   x = 725,357,119,041/390,118.50
6. Step 6: Final answer
   x = 1,859,325.10