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Finding the Fourth Proportional to 400.71, 553.05 and 387.21

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Solution

The fourth proportional to 400.71, 553.05 and 387.21 is: 534.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    400.71 : 553.05 = 387.21 : x
  2. Step 2: Convert to fraction form
    400.71/553.05 = 387.21/x
  3. Step 3: Cross multiply
    400.71x = 553.05 × 387.21
  4. Step 4: Simplify right side
    400.71x = 214,146.49
  5. Step 5: Solve for x
    x = 214,146.49/400.71
  6. Step 6: Final answer
    x = 534.42

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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.