Finding the Fourth Proportional to 2,658.28, 3,987.78 and 926.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,658.28 : 3,987.78 = 926.50 : x
2. Step 2: Convert to fraction form
   2,658.28/3,987.78 = 926.50/x
3. Step 3: Cross multiply
   2,658.28x = 3,987.78 × 926.50
4. Step 4: Simplify right side
   2,658.28x = 3,694,678.17
5. Step 5: Solve for x
   x = 3,694,678.17/2,658.28
6. Step 6: Final answer
   x = 1,389.88