Finding the Fourth Proportional to 1,216.55, 1,678.69 and 719.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,216.55 : 1,678.69 = 719.15 : x
2. Step 2: Convert to fraction form
   1,216.55/1,678.69 = 719.15/x
3. Step 3: Cross multiply
   1,216.55x = 1,678.69 × 719.15
4. Step 4: Simplify right side
   1,216.55x = 1,207,222.42
5. Step 5: Solve for x
   x = 1,207,222.42/1,216.55
6. Step 6: Final answer
   x = 992.33