Finding the Fourth Proportional to 1,111.05, 1,533.60 and 718.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.05 : 1,533.60 = 718.20 : x
2. Step 2: Convert to fraction form
   1,111.05/1,533.60 = 718.20/x
3. Step 3: Cross multiply
   1,111.05x = 1,533.60 × 718.20
4. Step 4: Simplify right side
   1,111.05x = 1,101,431.52
5. Step 5: Solve for x
   x = 1,101,431.52/1,111.05
6. Step 6: Final answer
   x = 991.34