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Finding the Fourth Proportional to 658.38, 987.72 and 219.78

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Solution

The fourth proportional to 658.38, 987.72 and 219.78 is: 329.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    658.38 : 987.72 = 219.78 : x
  2. Step 2: Convert to fraction form
    658.38/987.72 = 219.78/x
  3. Step 3: Cross multiply
    658.38x = 987.72 × 219.78
  4. Step 4: Simplify right side
    658.38x = 217,081.10
  5. Step 5: Solve for x
    x = 217,081.10/658.38
  6. Step 6: Final answer
    x = 329.72

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1.5x scale

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.