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Finding the Fourth Proportional to 318.29, 477.39 and 87.20

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Solution

The fourth proportional to 318.29, 477.39 and 87.20 is: 130.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.29 : 477.39 = 87.20 : x
  2. Step 2: Convert to fraction form
    318.29/477.39 = 87.20/x
  3. Step 3: Cross multiply
    318.29x = 477.39 × 87.20
  4. Step 4: Simplify right side
    318.29x = 41,626.24
  5. Step 5: Solve for x
    x = 41,626.24/318.29
  6. Step 6: Final answer
    x = 130.78

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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.