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Finding the Fourth Proportional to 426.77, 643.29 and 391.66

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Solution

The fourth proportional to 426.77, 643.29 and 391.66 is: 590.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.77 : 643.29 = 391.66 : x
  2. Step 2: Convert to fraction form
    426.77/643.29 = 391.66/x
  3. Step 3: Cross multiply
    426.77x = 643.29 × 391.66
  4. Step 4: Simplify right side
    426.77x = 251,949.35
  5. Step 5: Solve for x
    x = 251,949.35/426.77
  6. Step 6: Final answer
    x = 590.37

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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.