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Finding the Fourth Proportional to 387.90, 581.85 and 258.30

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Solution

The fourth proportional to 387.90, 581.85 and 258.30 is: 387.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.90 : 581.85 = 258.30 : x
  2. Step 2: Convert to fraction form
    387.90/581.85 = 258.30/x
  3. Step 3: Cross multiply
    387.90x = 581.85 × 258.30
  4. Step 4: Simplify right side
    387.90x = 150,291.86
  5. Step 5: Solve for x
    x = 150,291.86/387.90
  6. Step 6: Final answer
    x = 387.45

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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.