Finding the Fourth Proportional to 1,387.55, 1,914.59 and 890.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.55 : 1,914.59 = 890.09 : x
2. Step 2: Convert to fraction form
   1,387.55/1,914.59 = 890.09/x
3. Step 3: Cross multiply
   1,387.55x = 1,914.59 × 890.09
4. Step 4: Simplify right side
   1,387.55x = 1,704,143.39
5. Step 5: Solve for x
   x = 1,704,143.39/1,387.55
6. Step 6: Final answer
   x = 1,228.17