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Finding the Fourth Proportional to 579.78, 869.67 and 387

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Solution

The fourth proportional to 579.78, 869.67 and 387 is: 580.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    579.78 : 869.67 = 387 : x
  2. Step 2: Convert to fraction form
    579.78/869.67 = 387/x
  3. Step 3: Cross multiply
    579.78x = 869.67 × 387
  4. Step 4: Simplify right side
    579.78x = 336,562.29
  5. Step 5: Solve for x
    x = 336,562.29/579.78
  6. Step 6: Final answer
    x = 580.50

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Find fourth proportional to 289.89, 434.84 and 193.50
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Double scale
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Similar ratio
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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.