Finding the Fourth Proportional to 1,152.76, 1,726.78 and 781.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,152.76 : 1,726.78 = 781.40 : x
2. Step 2: Convert to fraction form
   1,152.76/1,726.78 = 781.40/x
3. Step 3: Cross multiply
   1,152.76x = 1,726.78 × 781.40
4. Step 4: Simplify right side
   1,152.76x = 1,349,305.89
5. Step 5: Solve for x
   x = 1,349,305.89/1,152.76
6. Step 6: Final answer
   x = 1,170.50