Finding the Fourth Proportional to 86.00, 128.96 and 42.65

Step by Step Solution

1. Step 1: Write the proportion equation
   86.00 : 128.96 = 42.65 : x
2. Step 2: Convert to fraction form
   86.00/128.96 = 42.65/x
3. Step 3: Cross multiply
   86.00x = 128.96 × 42.65
4. Step 4: Simplify right side
   86.00x = 5,499.93
5. Step 5: Solve for x
   x = 5,499.93/86.00
6. Step 6: Final answer
   x = 63.96