Finding the Fourth Proportional to 90.92, 136.38 and 42.78

Step by Step Solution

1. Step 1: Write the proportion equation
   90.92 : 136.38 = 42.78 : x
2. Step 2: Convert to fraction form
   90.92/136.38 = 42.78/x
3. Step 3: Cross multiply
   90.92x = 136.38 × 42.78
4. Step 4: Simplify right side
   90.92x = 5,834.34
5. Step 5: Solve for x
   x = 5,834.34/90.92
6. Step 6: Final answer
   x = 64.17