Finding the Fourth Proportional to 1,141.55, 1,575.35 and 644.19

Step by Step Solution

1. Step 1: Write the proportion equation
   1,141.55 : 1,575.35 = 644.19 : x
2. Step 2: Convert to fraction form
   1,141.55/1,575.35 = 644.19/x
3. Step 3: Cross multiply
   1,141.55x = 1,575.35 × 644.19
4. Step 4: Simplify right side
   1,141.55x = 1,014,821.50
5. Step 5: Solve for x
   x = 1,014,821.50/1,141.55
6. Step 6: Final answer
   x = 888.99