Finding the Fourth Proportional to 1,355.21, 1,870.25 and 765.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.21 : 1,870.25 = 765.89 : x
2. Step 2: Convert to fraction form
   1,355.21/1,870.25 = 765.89/x
3. Step 3: Cross multiply
   1,355.21x = 1,870.25 × 765.89
4. Step 4: Simplify right side
   1,355.21x = 1,432,405.77
5. Step 5: Solve for x
   x = 1,432,405.77/1,355.21
6. Step 6: Final answer
   x = 1,056.96