Finding the Fourth Proportional to 105.30, 145.28 and 77.69

Step by Step Solution

1. Step 1: Write the proportion equation
   105.30 : 145.28 = 77.69 : x
2. Step 2: Convert to fraction form
   105.30/145.28 = 77.69/x
3. Step 3: Cross multiply
   105.30x = 145.28 × 77.69
4. Step 4: Simplify right side
   105.30x = 11,285.69
5. Step 5: Solve for x
   x = 11,285.69/105.30
6. Step 6: Final answer
   x = 107.18