Finding the Fourth Proportional to 1,405.34, 2,105.59 and 993.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.34 : 2,105.59 = 993.80 : x
2. Step 2: Convert to fraction form
   1,405.34/2,105.59 = 993.80/x
3. Step 3: Cross multiply
   1,405.34x = 2,105.59 × 993.80
4. Step 4: Simplify right side
   1,405.34x = 2,092,535.34
5. Step 5: Solve for x
   x = 2,092,535.34/1,405.34
6. Step 6: Final answer
   x = 1,488.99