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Finding the Fourth Proportional to 679.78, 1,020.48 and 355.78

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Solution

The fourth proportional to 679.78, 1,020.48 and 355.78 is: 534.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.78 : 1,020.48 = 355.78 : x
  2. Step 2: Convert to fraction form
    679.78/1,020.48 = 355.78/x
  3. Step 3: Cross multiply
    679.78x = 1,020.48 × 355.78
  4. Step 4: Simplify right side
    679.78x = 363,066.37
  5. Step 5: Solve for x
    x = 363,066.37/679.78
  6. Step 6: Final answer
    x = 534.09

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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.