Finding the Fourth Proportional to 3,428.56, 5,142.78 and 1,120

Step by Step Solution

1. Step 1: Write the proportion equation
   3,428.56 : 5,142.78 = 1,120 : x
2. Step 2: Convert to fraction form
   3,428.56/5,142.78 = 1,120/x
3. Step 3: Cross multiply
   3,428.56x = 5,142.78 × 1,120
4. Step 4: Simplify right side
   3,428.56x = 5,759,913.60
5. Step 5: Solve for x
   x = 5,759,913.60/3,428.56
6. Step 6: Final answer
   x = 1,679.98