Finding the Fourth Proportional to 90.39, 124.71 and 55.42

Step by Step Solution

1. Step 1: Write the proportion equation
   90.39 : 124.71 = 55.42 : x
2. Step 2: Convert to fraction form
   90.39/124.71 = 55.42/x
3. Step 3: Cross multiply
   90.39x = 124.71 × 55.42
4. Step 4: Simplify right side
   90.39x = 6,911.73
5. Step 5: Solve for x
   x = 6,911.73/90.39
6. Step 6: Final answer
   x = 76.47