Finding the Fourth Proportional to 7,221.72, 10,830.72 and 2,839.20

Step by Step Solution

1. Step 1: Write the proportion equation
   7,221.72 : 10,830.72 = 2,839.20 : x
2. Step 2: Convert to fraction form
   7,221.72/10,830.72 = 2,839.20/x
3. Step 3: Cross multiply
   7,221.72x = 10,830.72 × 2,839.20
4. Step 4: Simplify right side
   7,221.72x = 30,750,580.22
5. Step 5: Solve for x
   x = 30,750,580.22/7,221.72
6. Step 6: Final answer
   x = 4,258.07