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Finding the Fourth Proportional to 386.34, 579.12 and 142.70

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Solution

The fourth proportional to 386.34, 579.12 and 142.70 is: 213.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.34 : 579.12 = 142.70 : x
  2. Step 2: Convert to fraction form
    386.34/579.12 = 142.70/x
  3. Step 3: Cross multiply
    386.34x = 579.12 × 142.70
  4. Step 4: Simplify right side
    386.34x = 82,637.53
  5. Step 5: Solve for x
    x = 82,637.53/386.34
  6. Step 6: Final answer
    x = 213.90

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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.