Finding the Fourth Proportional to 1,393.61, 2,088.72 and 776.66

Step by Step Solution

1. Step 1: Write the proportion equation
   1,393.61 : 2,088.72 = 776.66 : x
2. Step 2: Convert to fraction form
   1,393.61/2,088.72 = 776.66/x
3. Step 3: Cross multiply
   1,393.61x = 2,088.72 × 776.66
4. Step 4: Simplify right side
   1,393.61x = 1,622,214.83
5. Step 5: Solve for x
   x = 1,622,214.83/1,393.61
6. Step 6: Final answer
   x = 1,164.04