Finding the Fourth Proportional to 1,086.60, 1,499.37 and 644.41

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.60 : 1,499.37 = 644.41 : x
2. Step 2: Convert to fraction form
   1,086.60/1,499.37 = 644.41/x
3. Step 3: Cross multiply
   1,086.60x = 1,499.37 × 644.41
4. Step 4: Simplify right side
   1,086.60x = 966,214.51
5. Step 5: Solve for x
   x = 966,214.51/1,086.60
6. Step 6: Final answer
   x = 889.21