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Finding the Fourth Proportional to 548.20, 821.20 and 515.40

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Solution

The fourth proportional to 548.20, 821.20 and 515.40 is: 772.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    548.20 : 821.20 = 515.40 : x
  2. Step 2: Convert to fraction form
    548.20/821.20 = 515.40/x
  3. Step 3: Cross multiply
    548.20x = 821.20 × 515.40
  4. Step 4: Simplify right side
    548.20x = 423,246.48
  5. Step 5: Solve for x
    x = 423,246.48/548.20
  6. Step 6: Final answer
    x = 772.07

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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.