Finding the Fourth Proportional to 105.30, 145.35 and 72.60

Step by Step Solution

1. Step 1: Write the proportion equation
   105.30 : 145.35 = 72.60 : x
2. Step 2: Convert to fraction form
   105.30/145.35 = 72.60/x
3. Step 3: Cross multiply
   105.30x = 145.35 × 72.60
4. Step 4: Simplify right side
   105.30x = 10,552.41
5. Step 5: Solve for x
   x = 10,552.41/105.30
6. Step 6: Final answer
   x = 100.21