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Finding the Fourth Proportional to 805.38, 1,207.80 and 318.30

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Solution

The fourth proportional to 805.38, 1,207.80 and 318.30 is: 477.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.38 : 1,207.80 = 318.30 : x
  2. Step 2: Convert to fraction form
    805.38/1,207.80 = 318.30/x
  3. Step 3: Cross multiply
    805.38x = 1,207.80 × 318.30
  4. Step 4: Simplify right side
    805.38x = 384,442.74
  5. Step 5: Solve for x
    x = 384,442.74/805.38
  6. Step 6: Final answer
    x = 477.34

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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.