Finding the Fourth Proportional to 78.33, 108.20 and 55.15

Step by Step Solution

1. Step 1: Write the proportion equation
   78.33 : 108.20 = 55.15 : x
2. Step 2: Convert to fraction form
   78.33/108.20 = 55.15/x
3. Step 3: Cross multiply
   78.33x = 108.20 × 55.15
4. Step 4: Simplify right side
   78.33x = 5,967.10
5. Step 5: Solve for x
   x = 5,967.10/78.33
6. Step 6: Final answer
   x = 76.18