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Finding the Fourth Proportional to 638.79, 957.12 and 391.69

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Solution

The fourth proportional to 638.79, 957.12 and 391.69 is: 586.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.79 : 957.12 = 391.69 : x
  2. Step 2: Convert to fraction form
    638.79/957.12 = 391.69/x
  3. Step 3: Cross multiply
    638.79x = 957.12 × 391.69
  4. Step 4: Simplify right side
    638.79x = 374,894.33
  5. Step 5: Solve for x
    x = 374,894.33/638.79
  6. Step 6: Final answer
    x = 586.88

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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.