Finding the Fourth Proportional to 2,658.72, 3,987.08 and 879.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,658.72 : 3,987.08 = 879.40 : x
2. Step 2: Convert to fraction form
   2,658.72/3,987.08 = 879.40/x
3. Step 3: Cross multiply
   2,658.72x = 3,987.08 × 879.40
4. Step 4: Simplify right side
   2,658.72x = 3,506,238.15
5. Step 5: Solve for x
   x = 3,506,238.15/2,658.72
6. Step 6: Final answer
   x = 1,318.77