Finding the Fourth Proportional to 1,558.67, 2,150.87 and 999.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,558.67 : 2,150.87 = 999.15 : x
2. Step 2: Convert to fraction form
   1,558.67/2,150.87 = 999.15/x
3. Step 3: Cross multiply
   1,558.67x = 2,150.87 × 999.15
4. Step 4: Simplify right side
   1,558.67x = 2,149,036.76
5. Step 5: Solve for x
   x = 2,149,036.76/1,558.67
6. Step 6: Final answer
   x = 1,378.77