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Finding the Fourth Proportional to 258.95, 390.33 and 255.31

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Solution

The fourth proportional to 258.95, 390.33 and 255.31 is: 384.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.95 : 390.33 = 255.31 : x
  2. Step 2: Convert to fraction form
    258.95/390.33 = 255.31/x
  3. Step 3: Cross multiply
    258.95x = 390.33 × 255.31
  4. Step 4: Simplify right side
    258.95x = 99,654.18
  5. Step 5: Solve for x
    x = 99,654.18/258.95
  6. Step 6: Final answer
    x = 384.84

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.