Finding the Third Proportional to 138,406.50 and 206,889

Step by Step Solution

1. Step 1: Write the proportion equation
   138,406.50 : 206,889 = 206,889 : x
2. Step 2: Convert to fraction form
   138,406.50/206,889 = 206,889/x
3. Step 3: Cross multiply
   138,406.50x = 206,889 × 206,889
4. Step 4: Simplify right side
   138,406.50x = 42,803,058,321
5. Step 5: Solve for x
   x = 42,803,058,321/138,406.50
6. Step 6: Final answer
   x = 309,256.13