Finding the Fourth Proportional to 1,587.62, 2,191.72 and 998.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,587.62 : 2,191.72 = 998.48 : x
2. Step 2: Convert to fraction form
   1,587.62/2,191.72 = 998.48/x
3. Step 3: Cross multiply
   1,587.62x = 2,191.72 × 998.48
4. Step 4: Simplify right side
   1,587.62x = 2,188,388.59
5. Step 5: Solve for x
   x = 2,188,388.59/1,587.62
6. Step 6: Final answer
   x = 1,378.41