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Finding the Fourth Proportional to 521, 778.72 and 429.20

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Solution

The fourth proportional to 521, 778.72 and 429.20 is: 641.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    521 : 778.72 = 429.20 : x
  2. Step 2: Convert to fraction form
    521/778.72 = 429.20/x
  3. Step 3: Cross multiply
    521x = 778.72 × 429.20
  4. Step 4: Simplify right side
    521x = 334,226.62
  5. Step 5: Solve for x
    x = 334,226.62/521
  6. Step 6: Final answer
    x = 641.51

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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.