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Finding the Fourth Proportional to 939.12, 1,408.68 and 509

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Solution

The fourth proportional to 939.12, 1,408.68 and 509 is: 763.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.12 : 1,408.68 = 509 : x
  2. Step 2: Convert to fraction form
    939.12/1,408.68 = 509/x
  3. Step 3: Cross multiply
    939.12x = 1,408.68 × 509
  4. Step 4: Simplify right side
    939.12x = 717,018.12
  5. Step 5: Solve for x
    x = 717,018.12/939.12
  6. Step 6: Final answer
    x = 763.50

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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.