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Finding the Fourth Proportional to 817.20, 1,220.25 and 709.20

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Solution

The fourth proportional to 817.20, 1,220.25 and 709.20 is: 1,058.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.20 : 1,220.25 = 709.20 : x
  2. Step 2: Convert to fraction form
    817.20/1,220.25 = 709.20/x
  3. Step 3: Cross multiply
    817.20x = 1,220.25 × 709.20
  4. Step 4: Simplify right side
    817.20x = 865,401.30
  5. Step 5: Solve for x
    x = 865,401.30/817.20
  6. Step 6: Final answer
    x = 1,058.98

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.