Finding the Fourth Proportional to 10,128, 15,199.20 and 3,972

Step by Step Solution

1. Step 1: Write the proportion equation
   10,128 : 15,199.20 = 3,972 : x
2. Step 2: Convert to fraction form
   10,128/15,199.20 = 3,972/x
3. Step 3: Cross multiply
   10,128x = 15,199.20 × 3,972
4. Step 4: Simplify right side
   10,128x = 60,371,222.40
5. Step 5: Solve for x
   x = 60,371,222.40/10,128
6. Step 6: Final answer
   x = 5,960.82