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Finding the Fourth Proportional to 390.70, 585.73 and 217.42

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Solution

The fourth proportional to 390.70, 585.73 and 217.42 is: 325.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.70 : 585.73 = 217.42 : x
  2. Step 2: Convert to fraction form
    390.70/585.73 = 217.42/x
  3. Step 3: Cross multiply
    390.70x = 585.73 × 217.42
  4. Step 4: Simplify right side
    390.70x = 127,349.42
  5. Step 5: Solve for x
    x = 127,349.42/390.70
  6. Step 6: Final answer
    x = 325.95

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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.