Finding the Fourth Proportional to 1,290.05, 1,930.45 and 1,117.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.05 : 1,930.45 = 1,117.31 : x
2. Step 2: Convert to fraction form
   1,290.05/1,930.45 = 1,117.31/x
3. Step 3: Cross multiply
   1,290.05x = 1,930.45 × 1,117.31
4. Step 4: Simplify right side
   1,290.05x = 2,156,911.09
5. Step 5: Solve for x
   x = 2,156,911.09/1,290.05
6. Step 6: Final answer
   x = 1,671.96