Finding the Fourth Proportional to 1,355.16, 1,871.10 and 890.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.16 : 1,871.10 = 890.76 : x
2. Step 2: Convert to fraction form
   1,355.16/1,871.10 = 890.76/x
3. Step 3: Cross multiply
   1,355.16x = 1,871.10 × 890.76
4. Step 4: Simplify right side
   1,355.16x = 1,666,701.04
5. Step 5: Solve for x
   x = 1,666,701.04/1,355.16
6. Step 6: Final answer
   x = 1,229.89