Finding the Fourth Proportional to 105.15, 157.31 and 69.15

Step by Step Solution

1. Step 1: Write the proportion equation
   105.15 : 157.31 = 69.15 : x
2. Step 2: Convert to fraction form
   105.15/157.31 = 69.15/x
3. Step 3: Cross multiply
   105.15x = 157.31 × 69.15
4. Step 4: Simplify right side
   105.15x = 10,878.16
5. Step 5: Solve for x
   x = 10,878.16/105.15
6. Step 6: Final answer
   x = 103.45