Finding the Fourth Proportional to 93.30, 128.57 and 78.55

Step by Step Solution

1. Step 1: Write the proportion equation
   93.30 : 128.57 = 78.55 : x
2. Step 2: Convert to fraction form
   93.30/128.57 = 78.55/x
3. Step 3: Cross multiply
   93.30x = 128.57 × 78.55
4. Step 4: Simplify right side
   93.30x = 10,098.39
5. Step 5: Solve for x
   x = 10,098.39/93.30
6. Step 6: Final answer
   x = 108.24