Finding the Fourth Proportional to 1,387.83, 1,914.99 and 890.51

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.83 : 1,914.99 = 890.51 : x
2. Step 2: Convert to fraction form
   1,387.83/1,914.99 = 890.51/x
3. Step 3: Cross multiply
   1,387.83x = 1,914.99 × 890.51
4. Step 4: Simplify right side
   1,387.83x = 1,705,308.17
5. Step 5: Solve for x
   x = 1,705,308.17/1,387.83
6. Step 6: Final answer
   x = 1,228.76