Finding the Third Proportional to 131.31 and 285.40

Step by Step Solution

1. Step 1: Write the proportion equation
   131.31 : 285.40 = 285.40 : x
2. Step 2: Convert to fraction form
   131.31/285.40 = 285.40/x
3. Step 3: Cross multiply
   131.31x = 285.40 × 285.40
4. Step 4: Simplify right side
   131.31x = 81,452.27
5. Step 5: Solve for x
   x = 81,452.27/131.31
6. Step 6: Final answer
   x = 620.31