Finding the Fourth Proportional to 1,087.43, 1,499.99 and 645.23

Step by Step Solution

1. Step 1: Write the proportion equation
   1,087.43 : 1,499.99 = 645.23 : x
2. Step 2: Convert to fraction form
   1,087.43/1,499.99 = 645.23/x
3. Step 3: Cross multiply
   1,087.43x = 1,499.99 × 645.23
4. Step 4: Simplify right side
   1,087.43x = 967,839.07
5. Step 5: Solve for x
   x = 967,839.07/1,087.43
6. Step 6: Final answer
   x = 890.03