Finding the Third Proportional to 87.57 and 139.89

Step by Step Solution

1. Step 1: Write the proportion equation
   87.57 : 139.89 = 139.89 : x
2. Step 2: Convert to fraction form
   87.57/139.89 = 139.89/x
3. Step 3: Cross multiply
   87.57x = 139.89 × 139.89
4. Step 4: Simplify right side
   87.57x = 19,569.52
5. Step 5: Solve for x
   x = 19,569.52/87.57
6. Step 6: Final answer
   x = 223.48