Finding the Third Proportional to 138,421.50 and 217,470

Step by Step Solution

1. Step 1: Write the proportion equation
   138,421.50 : 217,470 = 217,470 : x
2. Step 2: Convert to fraction form
   138,421.50/217,470 = 217,470/x
3. Step 3: Cross multiply
   138,421.50x = 217,470 × 217,470
4. Step 4: Simplify right side
   138,421.50x = 47,293,200,900
5. Step 5: Solve for x
   x = 47,293,200,900/138,421.50
6. Step 6: Final answer
   x = 341,660.80