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Finding the Fourth Proportional to 258.16, 387.42 and 142.72

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Solution

The fourth proportional to 258.16, 387.42 and 142.72 is: 214.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.16 : 387.42 = 142.72 : x
  2. Step 2: Convert to fraction form
    258.16/387.42 = 142.72/x
  3. Step 3: Cross multiply
    258.16x = 387.42 × 142.72
  4. Step 4: Simplify right side
    258.16x = 55,292.58
  5. Step 5: Solve for x
    x = 55,292.58/258.16
  6. Step 6: Final answer
    x = 214.18

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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.