Finding the Third Proportional to 139,278 and 212,181

Step by Step Solution

1. Step 1: Write the proportion equation
   139,278 : 212,181 = 212,181 : x
2. Step 2: Convert to fraction form
   139,278/212,181 = 212,181/x
3. Step 3: Cross multiply
   139,278x = 212,181 × 212,181
4. Step 4: Simplify right side
   139,278x = 45,020,776,761
5. Step 5: Solve for x
   x = 45,020,776,761/139,278
6. Step 6: Final answer
   x = 323,243.99