Finding the Fourth Proportional to 1,160.34, 1,740.91 and 639.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,160.34 : 1,740.91 = 639.69 : x
2. Step 2: Convert to fraction form
   1,160.34/1,740.91 = 639.69/x
3. Step 3: Cross multiply
   1,160.34x = 1,740.91 × 639.69
4. Step 4: Simplify right side
   1,160.34x = 1,113,642.72
5. Step 5: Solve for x
   x = 1,113,642.72/1,160.34
6. Step 6: Final answer
   x = 959.76