Finding the Fourth Proportional to 85.62, 128.34 and 40.00

Step by Step Solution

1. Step 1: Write the proportion equation
   85.62 : 128.34 = 40.00 : x
2. Step 2: Convert to fraction form
   85.62/128.34 = 40.00/x
3. Step 3: Cross multiply
   85.62x = 128.34 × 40.00
4. Step 4: Simplify right side
   85.62x = 5,132.89
5. Step 5: Solve for x
   x = 5,132.89/85.62
6. Step 6: Final answer
   x = 59.95