Finding the Fourth Proportional to 1,388.48, 1,914.34 and 890.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.48 : 1,914.34 = 890.24 : x
2. Step 2: Convert to fraction form
   1,388.48/1,914.34 = 890.24/x
3. Step 3: Cross multiply
   1,388.48x = 1,914.34 × 890.24
4. Step 4: Simplify right side
   1,388.48x = 1,704,222.04
5. Step 5: Solve for x
   x = 1,704,222.04/1,388.48
6. Step 6: Final answer
   x = 1,227.40