Finding the Fourth Proportional to 1,428.98, 2,138.61 and 1,105.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.98 : 2,138.61 = 1,105.79 : x
2. Step 2: Convert to fraction form
   1,428.98/2,138.61 = 1,105.79/x
3. Step 3: Cross multiply
   1,428.98x = 2,138.61 × 1,105.79
4. Step 4: Simplify right side
   1,428.98x = 2,364,853.55
5. Step 5: Solve for x
   x = 2,364,853.55/1,428.98
6. Step 6: Final answer
   x = 1,654.92