Finding the Fourth Proportional to 1,356.21, 1,870.83 and 858.65

Step by Step Solution

1. Step 1: Write the proportion equation
   1,356.21 : 1,870.83 = 858.65 : x
2. Step 2: Convert to fraction form
   1,356.21/1,870.83 = 858.65/x
3. Step 3: Cross multiply
   1,356.21x = 1,870.83 × 858.65
4. Step 4: Simplify right side
   1,356.21x = 1,606,378.83
5. Step 5: Solve for x
   x = 1,606,378.83/1,356.21
6. Step 6: Final answer
   x = 1,184.46