Finding the Fourth Proportional to 1,087.43, 1,500.84 and 645.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,087.43 : 1,500.84 = 645.30 : x
2. Step 2: Convert to fraction form
   1,087.43/1,500.84 = 645.30/x
3. Step 3: Cross multiply
   1,087.43x = 1,500.84 × 645.30
4. Step 4: Simplify right side
   1,087.43x = 968,492.05
5. Step 5: Solve for x
   x = 968,492.05/1,087.43
6. Step 6: Final answer
   x = 890.63