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Finding the Fourth Proportional to 426.40, 639.44 and 317.76

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Solution

The fourth proportional to 426.40, 639.44 and 317.76 is: 476.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.40 : 639.44 = 317.76 : x
  2. Step 2: Convert to fraction form
    426.40/639.44 = 317.76/x
  3. Step 3: Cross multiply
    426.40x = 639.44 × 317.76
  4. Step 4: Simplify right side
    426.40x = 203,188.45
  5. Step 5: Solve for x
    x = 203,188.45/426.40
  6. Step 6: Final answer
    x = 476.52

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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.