Finding the Fourth Proportional to 1,158.91, 1,599.30 and 661.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,158.91 : 1,599.30 = 661.55 : x
2. Step 2: Convert to fraction form
   1,158.91/1,599.30 = 661.55/x
3. Step 3: Cross multiply
   1,158.91x = 1,599.30 × 661.55
4. Step 4: Simplify right side
   1,158.91x = 1,058,008.92
5. Step 5: Solve for x
   x = 1,058,008.92/1,158.91
6. Step 6: Final answer
   x = 912.94