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Finding the Fourth Proportional to 805.78, 1,209.05 and 394.69

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Solution

The fourth proportional to 805.78, 1,209.05 and 394.69 is: 592.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.78 : 1,209.05 = 394.69 : x
  2. Step 2: Convert to fraction form
    805.78/1,209.05 = 394.69/x
  3. Step 3: Cross multiply
    805.78x = 1,209.05 × 394.69
  4. Step 4: Simplify right side
    805.78x = 477,199.94
  5. Step 5: Solve for x
    x = 477,199.94/805.78
  6. Step 6: Final answer
    x = 592.22

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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.