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Finding the Fourth Proportional to 390.65, 582.22 and 387.43

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Solution

The fourth proportional to 390.65, 582.22 and 387.43 is: 577.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.65 : 582.22 = 387.43 : x
  2. Step 2: Convert to fraction form
    390.65/582.22 = 387.43/x
  3. Step 3: Cross multiply
    390.65x = 582.22 × 387.43
  4. Step 4: Simplify right side
    390.65x = 225,569.49
  5. Step 5: Solve for x
    x = 225,569.49/390.65
  6. Step 6: Final answer
    x = 577.42

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.