Finding the Fourth Proportional to 128.30, 176.98 and 78.52

Step by Step Solution

1. Step 1: Write the proportion equation
   128.30 : 176.98 = 78.52 : x
2. Step 2: Convert to fraction form
   128.30/176.98 = 78.52/x
3. Step 3: Cross multiply
   128.30x = 176.98 × 78.52
4. Step 4: Simplify right side
   128.30x = 13,895.50
5. Step 5: Solve for x
   x = 13,895.50/128.30
6. Step 6: Final answer
   x = 108.31