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Finding the Fourth Proportional to 639, 880.92 and 491.40

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Solution

The fourth proportional to 639, 880.92 and 491.40 is: 677.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    639 : 880.92 = 491.40 : x
  2. Step 2: Convert to fraction form
    639/880.92 = 491.40/x
  3. Step 3: Cross multiply
    639x = 880.92 × 491.40
  4. Step 4: Simplify right side
    639x = 432,884.09
  5. Step 5: Solve for x
    x = 432,884.09/639
  6. Step 6: Final answer
    x = 677.44

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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.