Finding the Fourth Proportional to 1,130.61, 1,560.83 and 780.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,130.61 : 1,560.83 = 780.69 : x
2. Step 2: Convert to fraction form
   1,130.61/1,560.83 = 780.69/x
3. Step 3: Cross multiply
   1,130.61x = 1,560.83 × 780.69
4. Step 4: Simplify right side
   1,130.61x = 1,218,524.37
5. Step 5: Solve for x
   x = 1,218,524.37/1,130.61
6. Step 6: Final answer
   x = 1,077.76