Finding the Fourth Proportional to 1,098.58, 1,648.18 and 611.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,098.58 : 1,648.18 = 611.98 : x
2. Step 2: Convert to fraction form
   1,098.58/1,648.18 = 611.98/x
3. Step 3: Cross multiply
   1,098.58x = 1,648.18 × 611.98
4. Step 4: Simplify right side
   1,098.58x = 1,008,653.20
5. Step 5: Solve for x
   x = 1,008,653.20/1,098.58
6. Step 6: Final answer
   x = 918.14