Finding the Third Proportional to 139,276 and 212,178

Step by Step Solution

1. Step 1: Write the proportion equation
   139,276 : 212,178 = 212,178 : x
2. Step 2: Convert to fraction form
   139,276/212,178 = 212,178/x
3. Step 3: Cross multiply
   139,276x = 212,178 × 212,178
4. Step 4: Simplify right side
   139,276x = 45,019,503,684
5. Step 5: Solve for x
   x = 45,019,503,684/139,276
6. Step 6: Final answer
   x = 323,239.49