Finding the Fourth Proportional to 1,215.48, 1,677.56 and 718.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,215.48 : 1,677.56 = 718.50 : x
2. Step 2: Convert to fraction form
   1,215.48/1,677.56 = 718.50/x
3. Step 3: Cross multiply
   1,215.48x = 1,677.56 × 718.50
4. Step 4: Simplify right side
   1,215.48x = 1,205,326.86
5. Step 5: Solve for x
   x = 1,205,326.86/1,215.48
6. Step 6: Final answer
   x = 991.65