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Finding the Fourth Proportional to 687.81, 1,031.40 and 276.60

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Solution

The fourth proportional to 687.81, 1,031.40 and 276.60 is: 414.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.81 : 1,031.40 = 276.60 : x
  2. Step 2: Convert to fraction form
    687.81/1,031.40 = 276.60/x
  3. Step 3: Cross multiply
    687.81x = 1,031.40 × 276.60
  4. Step 4: Simplify right side
    687.81x = 285,285.24
  5. Step 5: Solve for x
    x = 285,285.24/687.81
  6. Step 6: Final answer
    x = 414.77

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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.