Finding the Fourth Proportional to 1,587.69, 2,190.98 and 999.22

Step by Step Solution

1. Step 1: Write the proportion equation
   1,587.69 : 2,190.98 = 999.22 : x
2. Step 2: Convert to fraction form
   1,587.69/2,190.98 = 999.22/x
3. Step 3: Cross multiply
   1,587.69x = 2,190.98 × 999.22
4. Step 4: Simplify right side
   1,587.69x = 2,189,271.04
5. Step 5: Solve for x
   x = 2,189,271.04/1,587.69
6. Step 6: Final answer
   x = 1,378.90