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Finding the Fourth Proportional to 257.90, 386.85 and 84.59

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Solution

The fourth proportional to 257.90, 386.85 and 84.59 is: 126.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.90 : 386.85 = 84.59 : x
  2. Step 2: Convert to fraction form
    257.90/386.85 = 84.59/x
  3. Step 3: Cross multiply
    257.90x = 386.85 × 84.59
  4. Step 4: Simplify right side
    257.90x = 32,722.02
  5. Step 5: Solve for x
    x = 32,722.02/257.90
  6. Step 6: Final answer
    x = 126.88

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.