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Finding the Fourth Proportional to 427.40, 639.73 and 221.69

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Solution

The fourth proportional to 427.40, 639.73 and 221.69 is: 331.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.40 : 639.73 = 221.69 : x
  2. Step 2: Convert to fraction form
    427.40/639.73 = 221.69/x
  3. Step 3: Cross multiply
    427.40x = 639.73 × 221.69
  4. Step 4: Simplify right side
    427.40x = 141,818.41
  5. Step 5: Solve for x
    x = 141,818.41/427.40
  6. Step 6: Final answer
    x = 331.82

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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.