Finding the Third Proportional to 81.87 and 178.69

Step by Step Solution

1. Step 1: Write the proportion equation
   81.87 : 178.69 = 178.69 : x
2. Step 2: Convert to fraction form
   81.87/178.69 = 178.69/x
3. Step 3: Cross multiply
   81.87x = 178.69 × 178.69
4. Step 4: Simplify right side
   81.87x = 31,930.27
5. Step 5: Solve for x
   x = 31,930.27/81.87
6. Step 6: Final answer
   x = 390.01