Finding the Fourth Proportional to 78.28, 107.98 and 55.00

Step by Step Solution

1. Step 1: Write the proportion equation
   78.28 : 107.98 = 55.00 : x
2. Step 2: Convert to fraction form
   78.28/107.98 = 55.00/x
3. Step 3: Cross multiply
   78.28x = 107.98 × 55.00
4. Step 4: Simplify right side
   78.28x = 5,938.49
5. Step 5: Solve for x
   x = 5,938.49/78.28
6. Step 6: Final answer
   x = 75.86