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Finding the Fourth Proportional to 257.70, 386.60 and 129.45

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Solution

The fourth proportional to 257.70, 386.60 and 129.45 is: 194.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.70 : 386.60 = 129.45 : x
  2. Step 2: Convert to fraction form
    257.70/386.60 = 129.45/x
  3. Step 3: Cross multiply
    257.70x = 386.60 × 129.45
  4. Step 4: Simplify right side
    257.70x = 50,045.37
  5. Step 5: Solve for x
    x = 50,045.37/257.70
  6. Step 6: Final answer
    x = 194.20

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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.