Finding the Fourth Proportional to 1,216.06, 1,677.64 and 718.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,216.06 : 1,677.64 = 718.72 : x
2. Step 2: Convert to fraction form
   1,216.06/1,677.64 = 718.72/x
3. Step 3: Cross multiply
   1,216.06x = 1,677.64 × 718.72
4. Step 4: Simplify right side
   1,216.06x = 1,205,753.42
5. Step 5: Solve for x
   x = 1,205,753.42/1,216.06
6. Step 6: Final answer
   x = 991.52