Finding the Fourth Proportional to 105.15, 145.24 and 72.34

Step by Step Solution

1. Step 1: Write the proportion equation
   105.15 : 145.24 = 72.34 : x
2. Step 2: Convert to fraction form
   105.15/145.24 = 72.34/x
3. Step 3: Cross multiply
   105.15x = 145.24 × 72.34
4. Step 4: Simplify right side
   105.15x = 10,506.66
5. Step 5: Solve for x
   x = 10,506.66/105.15
6. Step 6: Final answer
   x = 99.93