Finding the Third Proportional to 139,221 and 217,147.50

Step by Step Solution

1. Step 1: Write the proportion equation
   139,221 : 217,147.50 = 217,147.50 : x
2. Step 2: Convert to fraction form
   139,221/217,147.50 = 217,147.50/x
3. Step 3: Cross multiply
   139,221x = 217,147.50 × 217,147.50
4. Step 4: Simplify right side
   139,221x = 47,153,036,756.25
5. Step 5: Solve for x
   x = 47,153,036,756.25/139,221
6. Step 6: Final answer
   x = 338,691.98