Finding the Fourth Proportional to 100.55, 138.69 and 74.39

Step by Step Solution

1. Step 1: Write the proportion equation
   100.55 : 138.69 = 74.39 : x
2. Step 2: Convert to fraction form
   100.55/138.69 = 74.39/x
3. Step 3: Cross multiply
   100.55x = 138.69 × 74.39
4. Step 4: Simplify right side
   100.55x = 10,316.46
5. Step 5: Solve for x
   x = 10,316.46/100.55
6. Step 6: Final answer
   x = 102.61