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Finding the Fourth Proportional to 806.40, 1,209.20 and 395.73

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Solution

The fourth proportional to 806.40, 1,209.20 and 395.73 is: 593.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.40 : 1,209.20 = 395.73 : x
  2. Step 2: Convert to fraction form
    806.40/1,209.20 = 395.73/x
  3. Step 3: Cross multiply
    806.40x = 1,209.20 × 395.73
  4. Step 4: Simplify right side
    806.40x = 478,514.74
  5. Step 5: Solve for x
    x = 478,514.74/806.40
  6. Step 6: Final answer
    x = 593.40

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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.