Finding the Fourth Proportional to 85.59, 128.52 and 61.56

Step by Step Solution

1. Step 1: Write the proportion equation
   85.59 : 128.52 = 61.56 : x
2. Step 2: Convert to fraction form
   85.59/128.52 = 61.56/x
3. Step 3: Cross multiply
   85.59x = 128.52 × 61.56
4. Step 4: Simplify right side
   85.59x = 7,911.69
5. Step 5: Solve for x
   x = 7,911.69/85.59
6. Step 6: Final answer
   x = 92.44