Finding the Fourth Proportional to 1,558.50, 2,150.96 and 999.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,558.50 : 2,150.96 = 999.60 : x
2. Step 2: Convert to fraction form
   1,558.50/2,150.96 = 999.60/x
3. Step 3: Cross multiply
   1,558.50x = 2,150.96 × 999.60
4. Step 4: Simplify right side
   1,558.50x = 2,150,102.12
5. Step 5: Solve for x
   x = 2,150,102.12/1,558.50
6. Step 6: Final answer
   x = 1,379.60