Finding the Fourth Proportional to 1,087.35, 1,500.15 and 645.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,087.35 : 1,500.15 = 645.09 : x
2. Step 2: Convert to fraction form
   1,087.35/1,500.15 = 645.09/x
3. Step 3: Cross multiply
   1,087.35x = 1,500.15 × 645.09
4. Step 4: Simplify right side
   1,087.35x = 967,731.76
5. Step 5: Solve for x
   x = 967,731.76/1,087.35
6. Step 6: Final answer
   x = 889.99