Finding the Fourth Proportional to 105.53, 145.76 and 72.72

Step by Step Solution

1. Step 1: Write the proportion equation
   105.53 : 145.76 = 72.72 : x
2. Step 2: Convert to fraction form
   105.53/145.76 = 72.72/x
3. Step 3: Cross multiply
   105.53x = 145.76 × 72.72
4. Step 4: Simplify right side
   105.53x = 10,599.30
5. Step 5: Solve for x
   x = 10,599.30/105.53
6. Step 6: Final answer
   x = 100.44