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Finding the Fourth Proportional to 639.43, 882.81 and 491.77

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Solution

The fourth proportional to 639.43, 882.81 and 491.77 is: 678.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.43 : 882.81 = 491.77 : x
  2. Step 2: Convert to fraction form
    639.43/882.81 = 491.77/x
  3. Step 3: Cross multiply
    639.43x = 882.81 × 491.77
  4. Step 4: Simplify right side
    639.43x = 434,139.47
  5. Step 5: Solve for x
    x = 434,139.47/639.43
  6. Step 6: Final answer
    x = 678.95

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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.