Finding the Fourth Proportional to 100.72, 151.20 and 83.60

Step by Step Solution

1. Step 1: Write the proportion equation
   100.72 : 151.20 = 83.60 : x
2. Step 2: Convert to fraction form
   100.72/151.20 = 83.60/x
3. Step 3: Cross multiply
   100.72x = 151.20 × 83.60
4. Step 4: Simplify right side
   100.72x = 12,640.32
5. Step 5: Solve for x
   x = 12,640.32/100.72
6. Step 6: Final answer
   x = 125.50