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Finding the Fourth Proportional to 638.66, 881.76 and 491.02

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Solution

The fourth proportional to 638.66, 881.76 and 491.02 is: 677.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.66 : 881.76 = 491.02 : x
  2. Step 2: Convert to fraction form
    638.66/881.76 = 491.02/x
  3. Step 3: Cross multiply
    638.66x = 881.76 × 491.02
  4. Step 4: Simplify right side
    638.66x = 432,961.80
  5. Step 5: Solve for x
    x = 432,961.80/638.66
  6. Step 6: Final answer
    x = 677.92

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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.