Finding the Third Proportional to 120,840 and 161,280

Step by Step Solution

1. Step 1: Write the proportion equation
   120,840 : 161,280 = 161,280 : x
2. Step 2: Convert to fraction form
   120,840/161,280 = 161,280/x
3. Step 3: Cross multiply
   120,840x = 161,280 × 161,280
4. Step 4: Simplify right side
   120,840x = 26,011,238,400
5. Step 5: Solve for x
   x = 26,011,238,400/120,840
6. Step 6: Final answer
   x = 215,253.55