Finding the Fourth Proportional to 123.99, 171.23 and 100.92

Step by Step Solution

1. Step 1: Write the proportion equation
   123.99 : 171.23 = 100.92 : x
2. Step 2: Convert to fraction form
   123.99/171.23 = 100.92/x
3. Step 3: Cross multiply
   123.99x = 171.23 × 100.92
4. Step 4: Simplify right side
   123.99x = 17,280.03
5. Step 5: Solve for x
   x = 17,280.03/123.99
6. Step 6: Final answer
   x = 139.37