Finding the Fourth Proportional to 101.55, 139.98 and 76.89

Step by Step Solution

1. Step 1: Write the proportion equation
   101.55 : 139.98 = 76.89 : x
2. Step 2: Convert to fraction form
   101.55/139.98 = 76.89/x
3. Step 3: Cross multiply
   101.55x = 139.98 × 76.89
4. Step 4: Simplify right side
   101.55x = 10,763.06
5. Step 5: Solve for x
   x = 10,763.06/101.55
6. Step 6: Final answer
   x = 105.99