Finding the Fourth Proportional to 1,899.40, 2,620.20 and 1,113.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,899.40 : 2,620.20 = 1,113.31 : x
2. Step 2: Convert to fraction form
   1,899.40/2,620.20 = 1,113.31/x
3. Step 3: Cross multiply
   1,899.40x = 2,620.20 × 1,113.31
4. Step 4: Simplify right side
   1,899.40x = 2,917,094.86
5. Step 5: Solve for x
   x = 2,917,094.86/1,899.40
6. Step 6: Final answer
   x = 1,535.80