Finding the Fourth Proportional to 85.86, 128.69 and 61.46

Step by Step Solution

1. Step 1: Write the proportion equation
   85.86 : 128.69 = 61.46 : x
2. Step 2: Convert to fraction form
   85.86/128.69 = 61.46/x
3. Step 3: Cross multiply
   85.86x = 128.69 × 61.46
4. Step 4: Simplify right side
   85.86x = 7,909.05
5. Step 5: Solve for x
   x = 7,909.05/85.86
6. Step 6: Final answer
   x = 92.12