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Finding the Fourth Proportional to 439.80, 606.42 and 390.60

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Solution

The fourth proportional to 439.80, 606.42 and 390.60 is: 538.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    439.80 : 606.42 = 390.60 : x
  2. Step 2: Convert to fraction form
    439.80/606.42 = 390.60/x
  3. Step 3: Cross multiply
    439.80x = 606.42 × 390.60
  4. Step 4: Simplify right side
    439.80x = 236,867.65
  5. Step 5: Solve for x
    x = 236,867.65/439.80
  6. Step 6: Final answer
    x = 538.58

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.