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Finding the Fourth Proportional to 1,286.82, 1,929.84 and 420.93

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Solution

The fourth proportional to 1,286.82, 1,929.84 and 420.93 is: 631.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,286.82 : 1,929.84 = 420.93 : x
  2. Step 2: Convert to fraction form
    1,286.82/1,929.84 = 420.93/x
  3. Step 3: Cross multiply
    1,286.82x = 1,929.84 × 420.93
  4. Step 4: Simplify right side
    1,286.82x = 812,327.55
  5. Step 5: Solve for x
    x = 812,327.55/1,286.82
  6. Step 6: Final answer
    x = 631.27

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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.