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Finding the Fourth Proportional to 879.39, 1,320.91 and 638.82

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Solution

The fourth proportional to 879.39, 1,320.91 and 638.82 is: 959.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.39 : 1,320.91 = 638.82 : x
  2. Step 2: Convert to fraction form
    879.39/1,320.91 = 638.82/x
  3. Step 3: Cross multiply
    879.39x = 1,320.91 × 638.82
  4. Step 4: Simplify right side
    879.39x = 843,822.13
  5. Step 5: Solve for x
    x = 843,822.13/879.39
  6. Step 6: Final answer
    x = 959.55

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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.