Finding the Fourth Proportional to 1,087.39, 1,500.59 and 645.37

Step by Step Solution

1. Step 1: Write the proportion equation
   1,087.39 : 1,500.59 = 645.37 : x
2. Step 2: Convert to fraction form
   1,087.39/1,500.59 = 645.37/x
3. Step 3: Cross multiply
   1,087.39x = 1,500.59 × 645.37
4. Step 4: Simplify right side
   1,087.39x = 968,433.63
5. Step 5: Solve for x
   x = 968,433.63/1,087.39
6. Step 6: Final answer
   x = 890.60