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Finding the Fourth Proportional to 729.21, 1,098.17 and 639

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Solution

The fourth proportional to 729.21, 1,098.17 and 639 is: 962.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    729.21 : 1,098.17 = 639 : x
  2. Step 2: Convert to fraction form
    729.21/1,098.17 = 639/x
  3. Step 3: Cross multiply
    729.21x = 1,098.17 × 639
  4. Step 4: Simplify right side
    729.21x = 701,732.23
  5. Step 5: Solve for x
    x = 701,732.23/729.21
  6. Step 6: Final answer
    x = 962.32

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.