Finding the Third Proportional to 138,858 and 298,810.50

Step by Step Solution

1. Step 1: Write the proportion equation
   138,858 : 298,810.50 = 298,810.50 : x
2. Step 2: Convert to fraction form
   138,858/298,810.50 = 298,810.50/x
3. Step 3: Cross multiply
   138,858x = 298,810.50 × 298,810.50
4. Step 4: Simplify right side
   138,858x = 89,287,714,910.25
5. Step 5: Solve for x
   x = 89,287,714,910.25/138,858
6. Step 6: Final answer
   x = 643,014.55