Finding the Fourth Proportional to 90.77, 136.16 and 42.71

Step by Step Solution

1. Step 1: Write the proportion equation
   90.77 : 136.16 = 42.71 : x
2. Step 2: Convert to fraction form
   90.77/136.16 = 42.71/x
3. Step 3: Cross multiply
   90.77x = 136.16 × 42.71
4. Step 4: Simplify right side
   90.77x = 5,815.18
5. Step 5: Solve for x
   x = 5,815.18/90.77
6. Step 6: Final answer
   x = 64.07