Finding the Fourth Proportional to 78.46, 108.20 and 55.10

Step by Step Solution

1. Step 1: Write the proportion equation
   78.46 : 108.20 = 55.10 : x
2. Step 2: Convert to fraction form
   78.46/108.20 = 55.10/x
3. Step 3: Cross multiply
   78.46x = 108.20 × 55.10
4. Step 4: Simplify right side
   78.46x = 5,962.23
5. Step 5: Solve for x
   x = 5,962.23/78.46
6. Step 6: Final answer
   x = 75.99