Finding the Fourth Proportional to 1,039.77, 1,434.78 and 641.37

Step by Step Solution

1. Step 1: Write the proportion equation
   1,039.77 : 1,434.78 = 641.37 : x
2. Step 2: Convert to fraction form
   1,039.77/1,434.78 = 641.37/x
3. Step 3: Cross multiply
   1,039.77x = 1,434.78 × 641.37
4. Step 4: Simplify right side
   1,039.77x = 920,224.85
5. Step 5: Solve for x
   x = 920,224.85/1,039.77
6. Step 6: Final answer
   x = 885.03