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Finding the Fourth Proportional to 556.80, 768.08 and 391.20

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Solution

The fourth proportional to 556.80, 768.08 and 391.20 is: 539.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    556.80 : 768.08 = 391.20 : x
  2. Step 2: Convert to fraction form
    556.80/768.08 = 391.20/x
  3. Step 3: Cross multiply
    556.80x = 768.08 × 391.20
  4. Step 4: Simplify right side
    556.80x = 300,472.90
  5. Step 5: Solve for x
    x = 300,472.90/556.80
  6. Step 6: Final answer
    x = 539.64

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.