Finding the Fourth Proportional to 1,000.69, 1,380.71 and 558.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,000.69 : 1,380.71 = 558.50 : x
2. Step 2: Convert to fraction form
   1,000.69/1,380.71 = 558.50/x
3. Step 3: Cross multiply
   1,000.69x = 1,380.71 × 558.50
4. Step 4: Simplify right side
   1,000.69x = 771,121.03
5. Step 5: Solve for x
   x = 771,121.03/1,000.69
6. Step 6: Final answer
   x = 770.59