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Finding the Fourth Proportional to 438.21, 657.18 and 218.61

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Solution

The fourth proportional to 438.21, 657.18 and 218.61 is: 327.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    438.21 : 657.18 = 218.61 : x
  2. Step 2: Convert to fraction form
    438.21/657.18 = 218.61/x
  3. Step 3: Cross multiply
    438.21x = 657.18 × 218.61
  4. Step 4: Simplify right side
    438.21x = 143,666.12
  5. Step 5: Solve for x
    x = 143,666.12/438.21
  6. Step 6: Final answer
    x = 327.85

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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.