Finding the Fourth Proportional to 1,288.26, 1,931.59 and 876.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.26 : 1,931.59 = 876.15 : x
2. Step 2: Convert to fraction form
   1,288.26/1,931.59 = 876.15/x
3. Step 3: Cross multiply
   1,288.26x = 1,931.59 × 876.15
4. Step 4: Simplify right side
   1,288.26x = 1,692,348.54
5. Step 5: Solve for x
   x = 1,692,348.54/1,288.26
6. Step 6: Final answer
   x = 1,313.68