Finding the Fourth Proportional to 1,216.92, 1,678.86 and 774.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,216.92 : 1,678.86 = 774.72 : x
2. Step 2: Convert to fraction form
   1,216.92/1,678.86 = 774.72/x
3. Step 3: Cross multiply
   1,216.92x = 1,678.86 × 774.72
4. Step 4: Simplify right side
   1,216.92x = 1,300,646.42
5. Step 5: Solve for x
   x = 1,300,646.42/1,216.92
6. Step 6: Final answer
   x = 1,068.80