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Finding the Fourth Proportional to 257.10, 385.29 and 135.20

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Solution

The fourth proportional to 257.10, 385.29 and 135.20 is: 202.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.10 : 385.29 = 135.20 : x
  2. Step 2: Convert to fraction form
    257.10/385.29 = 135.20/x
  3. Step 3: Cross multiply
    257.10x = 385.29 × 135.20
  4. Step 4: Simplify right side
    257.10x = 52,089.28
  5. Step 5: Solve for x
    x = 52,089.28/257.10
  6. Step 6: Final answer
    x = 202.60

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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.