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Finding the Fourth Proportional to 398.90, 548.85 and 389.69

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Solution

The fourth proportional to 398.90, 548.85 and 389.69 is: 536.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.90 : 548.85 = 389.69 : x
  2. Step 2: Convert to fraction form
    398.90/548.85 = 389.69/x
  3. Step 3: Cross multiply
    398.90x = 548.85 × 389.69
  4. Step 4: Simplify right side
    398.90x = 213,878.61
  5. Step 5: Solve for x
    x = 213,878.61/398.90
  6. Step 6: Final answer
    x = 536.18

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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.