Finding the Fourth Proportional to 1,388.87, 1,915.92 and 940.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.87 : 1,915.92 = 940.76 : x
2. Step 2: Convert to fraction form
   1,388.87/1,915.92 = 940.76/x
3. Step 3: Cross multiply
   1,388.87x = 1,915.92 × 940.76
4. Step 4: Simplify right side
   1,388.87x = 1,802,418.50
5. Step 5: Solve for x
   x = 1,802,418.50/1,388.87
6. Step 6: Final answer
   x = 1,297.76