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Finding the Fourth Proportional to 425.84, 641.20 and 318.40

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Solution

The fourth proportional to 425.84, 641.20 and 318.40 is: 479.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.84 : 641.20 = 318.40 : x
  2. Step 2: Convert to fraction form
    425.84/641.20 = 318.40/x
  3. Step 3: Cross multiply
    425.84x = 641.20 × 318.40
  4. Step 4: Simplify right side
    425.84x = 204,158.08
  5. Step 5: Solve for x
    x = 204,158.08/425.84
  6. Step 6: Final answer
    x = 479.42

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.