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Finding the Fourth Proportional to 390.78, 585.98 and 130.69

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Solution

The fourth proportional to 390.78, 585.98 and 130.69 is: 195.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.78 : 585.98 = 130.69 : x
  2. Step 2: Convert to fraction form
    390.78/585.98 = 130.69/x
  3. Step 3: Cross multiply
    390.78x = 585.98 × 130.69
  4. Step 4: Simplify right side
    390.78x = 76,581.81
  5. Step 5: Solve for x
    x = 76,581.81/390.78
  6. Step 6: Final answer
    x = 195.97

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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.