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Finding the Fourth Proportional to 393.21, 542.61 and 218.57

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Solution

The fourth proportional to 393.21, 542.61 and 218.57 is: 301.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.21 : 542.61 = 218.57 : x
  2. Step 2: Convert to fraction form
    393.21/542.61 = 218.57/x
  3. Step 3: Cross multiply
    393.21x = 542.61 × 218.57
  4. Step 4: Simplify right side
    393.21x = 118,595.55
  5. Step 5: Solve for x
    x = 118,595.55/393.21
  6. Step 6: Final answer
    x = 301.61

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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.