Finding the Third Proportional to 139,428 and 215,440

Step by Step Solution

1. Step 1: Write the proportion equation
   139,428 : 215,440 = 215,440 : x
2. Step 2: Convert to fraction form
   139,428/215,440 = 215,440/x
3. Step 3: Cross multiply
   139,428x = 215,440 × 215,440
4. Step 4: Simplify right side
   139,428x = 46,414,393,600
5. Step 5: Solve for x
   x = 46,414,393,600/139,428
6. Step 6: Final answer
   x = 332,891.48