Finding the Fourth Proportional to 1,216.74, 1,678.71 and 719.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,216.74 : 1,678.71 = 719.55 : x
2. Step 2: Convert to fraction form
   1,216.74/1,678.71 = 719.55/x
3. Step 3: Cross multiply
   1,216.74x = 1,678.71 × 719.55
4. Step 4: Simplify right side
   1,216.74x = 1,207,915.78
5. Step 5: Solve for x
   x = 1,207,915.78/1,216.74
6. Step 6: Final answer
   x = 992.75