Finding the Fourth Proportional to 1,097.76, 1,644.74 and 788.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,097.76 : 1,644.74 = 788.10 : x
2. Step 2: Convert to fraction form
   1,097.76/1,644.74 = 788.10/x
3. Step 3: Cross multiply
   1,097.76x = 1,644.74 × 788.10
4. Step 4: Simplify right side
   1,097.76x = 1,296,219.59
5. Step 5: Solve for x
   x = 1,296,219.59/1,097.76
6. Step 6: Final answer
   x = 1,180.79