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Finding the Fourth Proportional to 257.70, 386.55 and 84.38

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Solution

The fourth proportional to 257.70, 386.55 and 84.38 is: 126.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.70 : 386.55 = 84.38 : x
  2. Step 2: Convert to fraction form
    257.70/386.55 = 84.38/x
  3. Step 3: Cross multiply
    257.70x = 386.55 × 84.38
  4. Step 4: Simplify right side
    257.70x = 32,617.09
  5. Step 5: Solve for x
    x = 32,617.09/257.70
  6. Step 6: Final answer
    x = 126.57

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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.