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Finding the Fourth Proportional to 390.24, 585.36 and 133.76

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Solution

The fourth proportional to 390.24, 585.36 and 133.76 is: 200.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.24 : 585.36 = 133.76 : x
  2. Step 2: Convert to fraction form
    390.24/585.36 = 133.76/x
  3. Step 3: Cross multiply
    390.24x = 585.36 × 133.76
  4. Step 4: Simplify right side
    390.24x = 78,297.75
  5. Step 5: Solve for x
    x = 78,297.75/390.24
  6. Step 6: Final answer
    x = 200.64

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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.