Finding the Fourth Proportional to 1,153.86, 1,591.82 and 780.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,153.86 : 1,591.82 = 780.71 : x
2. Step 2: Convert to fraction form
   1,153.86/1,591.82 = 780.71/x
3. Step 3: Cross multiply
   1,153.86x = 1,591.82 × 780.71
4. Step 4: Simplify right side
   1,153.86x = 1,242,743.78
5. Step 5: Solve for x
   x = 1,242,743.78/1,153.86
6. Step 6: Final answer
   x = 1,077.03