Finding the Fourth Proportional to 1,719.69, 2,580.89 and 989.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,719.69 : 2,580.89 = 989.88 : x
2. Step 2: Convert to fraction form
   1,719.69/2,580.89 = 989.88/x
3. Step 3: Cross multiply
   1,719.69x = 2,580.89 × 989.88
4. Step 4: Simplify right side
   1,719.69x = 2,554,766.44
5. Step 5: Solve for x
   x = 2,554,766.44/1,719.69
6. Step 6: Final answer
   x = 1,485.60