Finding the Fourth Proportional to 1,564.39, 2,158.78 and 856.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,564.39 : 2,158.78 = 856.10 : x
2. Step 2: Convert to fraction form
   1,564.39/2,158.78 = 856.10/x
3. Step 3: Cross multiply
   1,564.39x = 2,158.78 × 856.10
4. Step 4: Simplify right side
   1,564.39x = 1,848,126.72
5. Step 5: Solve for x
   x = 1,848,126.72/1,564.39
6. Step 6: Final answer
   x = 1,181.37