Finding the Fourth Proportional to 1,355.63, 1,870.00 and 857.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.63 : 1,870.00 = 857.40 : x
2. Step 2: Convert to fraction form
   1,355.63/1,870.00 = 857.40/x
3. Step 3: Cross multiply
   1,355.63x = 1,870.00 × 857.40
4. Step 4: Simplify right side
   1,355.63x = 1,603,338.60
5. Step 5: Solve for x
   x = 1,603,338.60/1,355.63
6. Step 6: Final answer
   x = 1,182.73