Finding the Fourth Proportional to 123.98, 171.10 and 71.55

Step by Step Solution

1. Step 1: Write the proportion equation
   123.98 : 171.10 = 71.55 : x
2. Step 2: Convert to fraction form
   123.98/171.10 = 71.55/x
3. Step 3: Cross multiply
   123.98x = 171.10 × 71.55
4. Step 4: Simplify right side
   123.98x = 12,241.85
5. Step 5: Solve for x
   x = 12,241.85/123.98
6. Step 6: Final answer
   x = 98.74