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Finding the Fourth Proportional to 805.28, 1,207.92 and 421.28

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Solution

The fourth proportional to 805.28, 1,207.92 and 421.28 is: 631.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.28 : 1,207.92 = 421.28 : x
  2. Step 2: Convert to fraction form
    805.28/1,207.92 = 421.28/x
  3. Step 3: Cross multiply
    805.28x = 1,207.92 × 421.28
  4. Step 4: Simplify right side
    805.28x = 508,872.54
  5. Step 5: Solve for x
    x = 508,872.54/805.28
  6. Step 6: Final answer
    x = 631.92

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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.