Finding the Fourth Proportional to 1,087.15, 1,500.71 and 645.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,087.15 : 1,500.71 = 645.09 : x
2. Step 2: Convert to fraction form
   1,087.15/1,500.71 = 645.09/x
3. Step 3: Cross multiply
   1,087.15x = 1,500.71 × 645.09
4. Step 4: Simplify right side
   1,087.15x = 968,093.01
5. Step 5: Solve for x
   x = 968,093.01/1,087.15
6. Step 6: Final answer
   x = 890.49