Finding the Fourth Proportional to 2,160.28, 2,980.86 and 1,228.76

Step by Step Solution

1. Step 1: Write the proportion equation
   2,160.28 : 2,980.86 = 1,228.76 : x
2. Step 2: Convert to fraction form
   2,160.28/2,980.86 = 1,228.76/x
3. Step 3: Cross multiply
   2,160.28x = 2,980.86 × 1,228.76
4. Step 4: Simplify right side
   2,160.28x = 3,662,761.53
5. Step 5: Solve for x
   x = 3,662,761.53/2,160.28
6. Step 6: Final answer
   x = 1,695.50