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Finding the Fourth Proportional to 390.25, 538.55 and 215.61

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Solution

The fourth proportional to 390.25, 538.55 and 215.61 is: 297.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.25 : 538.55 = 215.61 : x
  2. Step 2: Convert to fraction form
    390.25/538.55 = 215.61/x
  3. Step 3: Cross multiply
    390.25x = 538.55 × 215.61
  4. Step 4: Simplify right side
    390.25x = 116,116.77
  5. Step 5: Solve for x
    x = 116,116.77/390.25
  6. Step 6: Final answer
    x = 297.54

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.