Finding the Fourth Proportional to 101.25, 139.56 and 77.89

Step by Step Solution

1. Step 1: Write the proportion equation
   101.25 : 139.56 = 77.89 : x
2. Step 2: Convert to fraction form
   101.25/139.56 = 77.89/x
3. Step 3: Cross multiply
   101.25x = 139.56 × 77.89
4. Step 4: Simplify right side
   101.25x = 10,870.33
5. Step 5: Solve for x
   x = 10,870.33/101.25
6. Step 6: Final answer
   x = 107.36