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Finding the Fourth Proportional to 687.39, 1,031.42 and 276.81

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Solution

The fourth proportional to 687.39, 1,031.42 and 276.81 is: 415.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.39 : 1,031.42 = 276.81 : x
  2. Step 2: Convert to fraction form
    687.39/1,031.42 = 276.81/x
  3. Step 3: Cross multiply
    687.39x = 1,031.42 × 276.81
  4. Step 4: Simplify right side
    687.39x = 285,507.37
  5. Step 5: Solve for x
    x = 285,507.37/687.39
  6. Step 6: Final answer
    x = 415.35

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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.