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Finding the Fourth Proportional to 427.21, 640.24 and 221.35

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Solution

The fourth proportional to 427.21, 640.24 and 221.35 is: 331.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.21 : 640.24 = 221.35 : x
  2. Step 2: Convert to fraction form
    427.21/640.24 = 221.35/x
  3. Step 3: Cross multiply
    427.21x = 640.24 × 221.35
  4. Step 4: Simplify right side
    427.21x = 141,714.97
  5. Step 5: Solve for x
    x = 141,714.97/427.21
  6. Step 6: Final answer
    x = 331.72

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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.