Finding the Fourth Proportional to 78.39, 108.17 and 55.10

Step by Step Solution

1. Step 1: Write the proportion equation
   78.39 : 108.17 = 55.10 : x
2. Step 2: Convert to fraction form
   78.39/108.17 = 55.10/x
3. Step 3: Cross multiply
   78.39x = 108.17 × 55.10
4. Step 4: Simplify right side
   78.39x = 5,960.37
5. Step 5: Solve for x
   x = 5,960.37/78.39
6. Step 6: Final answer
   x = 76.03