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Finding the Fourth Proportional to 683.40, 1,025.20 and 318.20

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Solution

The fourth proportional to 683.40, 1,025.20 and 318.20 is: 477.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    683.40 : 1,025.20 = 318.20 : x
  2. Step 2: Convert to fraction form
    683.40/1,025.20 = 318.20/x
  3. Step 3: Cross multiply
    683.40x = 1,025.20 × 318.20
  4. Step 4: Simplify right side
    683.40x = 326,218.64
  5. Step 5: Solve for x
    x = 326,218.64/683.40
  6. Step 6: Final answer
    x = 477.35

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.