Finding the Fourth Proportional to 1,355.84, 1,870.20 and 890.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.84 : 1,870.20 = 890.12 : x
2. Step 2: Convert to fraction form
   1,355.84/1,870.20 = 890.12/x
3. Step 3: Cross multiply
   1,355.84x = 1,870.20 × 890.12
4. Step 4: Simplify right side
   1,355.84x = 1,664,702.42
5. Step 5: Solve for x
   x = 1,664,702.42/1,355.84
6. Step 6: Final answer
   x = 1,227.80