Finding the Fourth Proportional to 1,131.56, 1,697.53 and 390.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.56 : 1,697.53 = 390.98 : x
2. Step 2: Convert to fraction form
   1,131.56/1,697.53 = 390.98/x
3. Step 3: Cross multiply
   1,131.56x = 1,697.53 × 390.98
4. Step 4: Simplify right side
   1,131.56x = 663,704.10
5. Step 5: Solve for x
   x = 663,704.10/1,131.56
6. Step 6: Final answer
   x = 586.54