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Finding the Fourth Proportional to 612.78, 919.17 and 431.70

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Solution

The fourth proportional to 612.78, 919.17 and 431.70 is: 647.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.78 : 919.17 = 431.70 : x
  2. Step 2: Convert to fraction form
    612.78/919.17 = 431.70/x
  3. Step 3: Cross multiply
    612.78x = 919.17 × 431.70
  4. Step 4: Simplify right side
    612.78x = 396,805.69
  5. Step 5: Solve for x
    x = 396,805.69/612.78
  6. Step 6: Final answer
    x = 647.55

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Similar ratio
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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.