Finding the Third Proportional to 90.39 and 187.21

Step by Step Solution

1. Step 1: Write the proportion equation
   90.39 : 187.21 = 187.21 : x
2. Step 2: Convert to fraction form
   90.39/187.21 = 187.21/x
3. Step 3: Cross multiply
   90.39x = 187.21 × 187.21
4. Step 4: Simplify right side
   90.39x = 35,046.47
5. Step 5: Solve for x
   x = 35,046.47/90.39
6. Step 6: Final answer
   x = 387.74