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Finding the Fourth Proportional to 390.51, 585.89 and 207.89

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Solution

The fourth proportional to 390.51, 585.89 and 207.89 is: 311.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.51 : 585.89 = 207.89 : x
  2. Step 2: Convert to fraction form
    390.51/585.89 = 207.89/x
  3. Step 3: Cross multiply
    390.51x = 585.89 × 207.89
  4. Step 4: Simplify right side
    390.51x = 121,796.70
  5. Step 5: Solve for x
    x = 121,796.70/390.51
  6. Step 6: Final answer
    x = 311.89

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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.