Finding the Fourth Proportional to 3,587.52, 5,380.80 and 990.72

Step by Step Solution

1. Step 1: Write the proportion equation
   3,587.52 : 5,380.80 = 990.72 : x
2. Step 2: Convert to fraction form
   3,587.52/5,380.80 = 990.72/x
3. Step 3: Cross multiply
   3,587.52x = 5,380.80 × 990.72
4. Step 4: Simplify right side
   3,587.52x = 5,330,866.18
5. Step 5: Solve for x
   x = 5,330,866.18/3,587.52
6. Step 6: Final answer
   x = 1,485.95