Finding the Fourth Proportional to 918.34, 1,267.31 and 498.69

Step by Step Solution

1. Step 1: Write the proportion equation
   918.34 : 1,267.31 = 498.69 : x
2. Step 2: Convert to fraction form
   918.34/1,267.31 = 498.69/x
3. Step 3: Cross multiply
   918.34x = 1,267.31 × 498.69
4. Step 4: Simplify right side
   918.34x = 631,994.82
5. Step 5: Solve for x
   x = 631,994.82/918.34
6. Step 6: Final answer
   x = 688.19