Finding the Third Proportional to 139,099 and 218,440

Step by Step Solution

1. Step 1: Write the proportion equation
   139,099 : 218,440 = 218,440 : x
2. Step 2: Convert to fraction form
   139,099/218,440 = 218,440/x
3. Step 3: Cross multiply
   139,099x = 218,440 × 218,440
4. Step 4: Simplify right side
   139,099x = 47,716,033,600
5. Step 5: Solve for x
   x = 47,716,033,600/139,099
6. Step 6: Final answer
   x = 343,036.50