Finding the Fourth Proportional to 11,900.28, 17,830.94 and 7,221.72

Step by Step Solution

1. Step 1: Write the proportion equation
   11,900.28 : 17,830.94 = 7,221.72 : x
2. Step 2: Convert to fraction form
   11,900.28/17,830.94 = 7,221.72/x
3. Step 3: Cross multiply
   11,900.28x = 17,830.94 × 7,221.72
4. Step 4: Simplify right side
   11,900.28x = 128,770,056.02
5. Step 5: Solve for x
   x = 128,770,056.02/11,900.28
6. Step 6: Final answer
   x = 10,820.76