Finding the Fourth Proportional to 1,087.18, 1,499.72 and 688.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,087.18 : 1,499.72 = 688.12 : x
2. Step 2: Convert to fraction form
   1,087.18/1,499.72 = 688.12/x
3. Step 3: Cross multiply
   1,087.18x = 1,499.72 × 688.12
4. Step 4: Simplify right side
   1,087.18x = 1,031,980.14
5. Step 5: Solve for x
   x = 1,031,980.14/1,087.18
6. Step 6: Final answer
   x = 949.23