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Finding the Fourth Proportional to 258.17, 387.30 and 84.79

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Solution

The fourth proportional to 258.17, 387.30 and 84.79 is: 127.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.17 : 387.30 = 84.79 : x
  2. Step 2: Convert to fraction form
    258.17/387.30 = 84.79/x
  3. Step 3: Cross multiply
    258.17x = 387.30 × 84.79
  4. Step 4: Simplify right side
    258.17x = 32,839.17
  5. Step 5: Solve for x
    x = 32,839.17/258.17
  6. Step 6: Final answer
    x = 127.20

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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.