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Finding the Fourth Proportional to 258.55, 389.59 and 213.90

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Solution

The fourth proportional to 258.55, 389.59 and 213.90 is: 322.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.55 : 389.59 = 213.90 : x
  2. Step 2: Convert to fraction form
    258.55/389.59 = 213.90/x
  3. Step 3: Cross multiply
    258.55x = 389.59 × 213.90
  4. Step 4: Simplify right side
    258.55x = 83,333.30
  5. Step 5: Solve for x
    x = 83,333.30/258.55
  6. Step 6: Final answer
    x = 322.31

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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.