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Finding the Fourth Proportional to 547.40, 821.90 and 385.80

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Solution

The fourth proportional to 547.40, 821.90 and 385.80 is: 579.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    547.40 : 821.90 = 385.80 : x
  2. Step 2: Convert to fraction form
    547.40/821.90 = 385.80/x
  3. Step 3: Cross multiply
    547.40x = 821.90 × 385.80
  4. Step 4: Simplify right side
    547.40x = 317,089.02
  5. Step 5: Solve for x
    x = 317,089.02/547.40
  6. Step 6: Final answer
    x = 579.26

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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.