Finding the Fourth Proportional to 1,287.90, 1,930.18 and 1,114.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,287.90 : 1,930.18 = 1,114.56 : x
2. Step 2: Convert to fraction form
   1,287.90/1,930.18 = 1,114.56/x
3. Step 3: Cross multiply
   1,287.90x = 1,930.18 × 1,114.56
4. Step 4: Simplify right side
   1,287.90x = 2,151,301.42
5. Step 5: Solve for x
   x = 2,151,301.42/1,287.90
6. Step 6: Final answer
   x = 1,670.39