Finding the Fourth Proportional to 100.04, 137.78 and 78.18

Step by Step Solution

1. Step 1: Write the proportion equation
   100.04 : 137.78 = 78.18 : x
2. Step 2: Convert to fraction form
   100.04/137.78 = 78.18/x
3. Step 3: Cross multiply
   100.04x = 137.78 × 78.18
4. Step 4: Simplify right side
   100.04x = 10,771.64
5. Step 5: Solve for x
   x = 10,771.64/100.04
6. Step 6: Final answer
   x = 107.67