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Finding the Fourth Proportional to 398.64, 553.43 and 386.76

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Solution

The fourth proportional to 398.64, 553.43 and 386.76 is: 536.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.64 : 553.43 = 386.76 : x
  2. Step 2: Convert to fraction form
    398.64/553.43 = 386.76/x
  3. Step 3: Cross multiply
    398.64x = 553.43 × 386.76
  4. Step 4: Simplify right side
    398.64x = 214,044.59
  5. Step 5: Solve for x
    x = 214,044.59/398.64
  6. Step 6: Final answer
    x = 536.94

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.