Finding the Third Proportional to 212,139 and 248,406.75

Step by Step Solution

1. Step 1: Write the proportion equation
   212,139 : 248,406.75 = 248,406.75 : x
2. Step 2: Convert to fraction form
   212,139/248,406.75 = 248,406.75/x
3. Step 3: Cross multiply
   212,139x = 248,406.75 × 248,406.75
4. Step 4: Simplify right side
   212,139x = 61,705,913,445.56
5. Step 5: Solve for x
   x = 61,705,913,445.56/212,139
6. Step 6: Final answer
   x = 290,874.91