Finding the Fourth Proportional to 3,071.56, 4,607.28 and 991.72

Step by Step Solution

1. Step 1: Write the proportion equation
   3,071.56 : 4,607.28 = 991.72 : x
2. Step 2: Convert to fraction form
   3,071.56/4,607.28 = 991.72/x
3. Step 3: Cross multiply
   3,071.56x = 4,607.28 × 991.72
4. Step 4: Simplify right side
   3,071.56x = 4,569,131.72
5. Step 5: Solve for x
   x = 4,569,131.72/3,071.56
6. Step 6: Final answer
   x = 1,487.56