Finding the Fourth Proportional to 912.72, 1,259.59 and 498.72

Step by Step Solution

1. Step 1: Write the proportion equation
   912.72 : 1,259.59 = 498.72 : x
2. Step 2: Convert to fraction form
   912.72/1,259.59 = 498.72/x
3. Step 3: Cross multiply
   912.72x = 1,259.59 × 498.72
4. Step 4: Simplify right side
   912.72x = 628,180.23
5. Step 5: Solve for x
   x = 628,180.23/912.72
6. Step 6: Final answer
   x = 688.25