Finding the Fourth Proportional to 1,153.84, 1,591.32 and 780.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,153.84 : 1,591.32 = 780.72 : x
2. Step 2: Convert to fraction form
   1,153.84/1,591.32 = 780.72/x
3. Step 3: Cross multiply
   1,153.84x = 1,591.32 × 780.72
4. Step 4: Simplify right side
   1,153.84x = 1,242,375.35
5. Step 5: Solve for x
   x = 1,242,375.35/1,153.84
6. Step 6: Final answer
   x = 1,076.73