Finding the Fourth Proportional to 1,153.67, 1,729.42 and 639.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,153.67 : 1,729.42 = 639.59 : x
2. Step 2: Convert to fraction form
   1,153.67/1,729.42 = 639.59/x
3. Step 3: Cross multiply
   1,153.67x = 1,729.42 × 639.59
4. Step 4: Simplify right side
   1,153.67x = 1,106,109.49
5. Step 5: Solve for x
   x = 1,106,109.49/1,153.67
6. Step 6: Final answer
   x = 958.78