Finding the Fourth Proportional to 1,112.05, 1,668.39 and 1,112.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,112.05 : 1,668.39 = 1,112.05 : x
2. Step 2: Convert to fraction form
   1,112.05/1,668.39 = 1,112.05/x
3. Step 3: Cross multiply
   1,112.05x = 1,668.39 × 1,112.05
4. Step 4: Simplify right side
   1,112.05x = 1,855,333.10
5. Step 5: Solve for x
   x = 1,855,333.10/1,112.05
6. Step 6: Final answer
   x = 1,668.39