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Finding the Fourth Proportional to 408.40, 562.20 and 386.80

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Solution

The fourth proportional to 408.40, 562.20 and 386.80 is: 532.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    408.40 : 562.20 = 386.80 : x
  2. Step 2: Convert to fraction form
    408.40/562.20 = 386.80/x
  3. Step 3: Cross multiply
    408.40x = 562.20 × 386.80
  4. Step 4: Simplify right side
    408.40x = 217,458.96
  5. Step 5: Solve for x
    x = 217,458.96/408.40
  6. Step 6: Final answer
    x = 532.47

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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.