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Finding the Fourth Proportional to 258.35, 387.20 and 142.79

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Solution

The fourth proportional to 258.35, 387.20 and 142.79 is: 214.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.35 : 387.20 = 142.79 : x
  2. Step 2: Convert to fraction form
    258.35/387.20 = 142.79/x
  3. Step 3: Cross multiply
    258.35x = 387.20 × 142.79
  4. Step 4: Simplify right side
    258.35x = 55,286.71
  5. Step 5: Solve for x
    x = 55,286.71/258.35
  6. Step 6: Final answer
    x = 214.00

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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.