Finding the Fourth Proportional to 1,564.21, 2,158.59 and 856.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,564.21 : 2,158.59 = 856.09 : x
2. Step 2: Convert to fraction form
   1,564.21/2,158.59 = 856.09/x
3. Step 3: Cross multiply
   1,564.21x = 2,158.59 × 856.09
4. Step 4: Simplify right side
   1,564.21x = 1,847,948.41
5. Step 5: Solve for x
   x = 1,847,948.41/1,564.21
6. Step 6: Final answer
   x = 1,181.39