Finding the Fourth Proportional to 93.16, 128.60 and 78.56

Step by Step Solution

1. Step 1: Write the proportion equation
   93.16 : 128.60 = 78.56 : x
2. Step 2: Convert to fraction form
   93.16/128.60 = 78.56/x
3. Step 3: Cross multiply
   93.16x = 128.60 × 78.56
4. Step 4: Simplify right side
   93.16x = 10,102.82
5. Step 5: Solve for x
   x = 10,102.82/93.16
6. Step 6: Final answer
   x = 108.45