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Finding the Fourth Proportional to 257.75, 386.50 and 86.63

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Solution

The fourth proportional to 257.75, 386.50 and 86.63 is: 129.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.75 : 386.50 = 86.63 : x
  2. Step 2: Convert to fraction form
    257.75/386.50 = 86.63/x
  3. Step 3: Cross multiply
    257.75x = 386.50 × 86.63
  4. Step 4: Simplify right side
    257.75x = 33,480.13
  5. Step 5: Solve for x
    x = 33,480.13/257.75
  6. Step 6: Final answer
    x = 129.90

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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.