Finding the Fourth Proportional to 90.76, 136.18 and 39.42

Step by Step Solution

1. Step 1: Write the proportion equation
   90.76 : 136.18 = 39.42 : x
2. Step 2: Convert to fraction form
   90.76/136.18 = 39.42/x
3. Step 3: Cross multiply
   90.76x = 136.18 × 39.42
4. Step 4: Simplify right side
   90.76x = 5,368.22
5. Step 5: Solve for x
   x = 5,368.22/90.76
6. Step 6: Final answer
   x = 59.15