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Finding the Fourth Proportional to 909.78, 1,365.12 and 422.76

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Solution

The fourth proportional to 909.78, 1,365.12 and 422.76 is: 634.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    909.78 : 1,365.12 = 422.76 : x
  2. Step 2: Convert to fraction form
    909.78/1,365.12 = 422.76/x
  3. Step 3: Cross multiply
    909.78x = 1,365.12 × 422.76
  4. Step 4: Simplify right side
    909.78x = 577,118.13
  5. Step 5: Solve for x
    x = 577,118.13/909.78
  6. Step 6: Final answer
    x = 634.35

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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.