Finding the Fourth Proportional to 1,290.14, 1,780.89 and 871.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.14 : 1,780.89 = 871.69 : x
2. Step 2: Convert to fraction form
   1,290.14/1,780.89 = 871.69/x
3. Step 3: Cross multiply
   1,290.14x = 1,780.89 × 871.69
4. Step 4: Simplify right side
   1,290.14x = 1,552,375.10
5. Step 5: Solve for x
   x = 1,552,375.10/1,290.14
6. Step 6: Final answer
   x = 1,203.26