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Finding the Fourth Proportional to 257.59, 386.39 and 86.59

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Solution

The fourth proportional to 257.59, 386.39 and 86.59 is: 129.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.59 : 386.39 = 86.59 : x
  2. Step 2: Convert to fraction form
    257.59/386.39 = 86.59/x
  3. Step 3: Cross multiply
    257.59x = 386.39 × 86.59
  4. Step 4: Simplify right side
    257.59x = 33,457.51
  5. Step 5: Solve for x
    x = 33,457.51/257.59
  6. Step 6: Final answer
    x = 129.89

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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.