Finding the Third Proportional to 286.88 and 385.31

Step by Step Solution

1. Step 1: Write the proportion equation
   286.88 : 385.31 = 385.31 : x
2. Step 2: Convert to fraction form
   286.88/385.31 = 385.31/x
3. Step 3: Cross multiply
   286.88x = 385.31 × 385.31
4. Step 4: Simplify right side
   286.88x = 148,465.72
5. Step 5: Solve for x
   x = 148,465.72/286.88
6. Step 6: Final answer
   x = 517.53