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Finding the Fourth Proportional to 687.40, 1,031.42 and 276.84

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Solution

The fourth proportional to 687.40, 1,031.42 and 276.84 is: 415.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.40 : 1,031.42 = 276.84 : x
  2. Step 2: Convert to fraction form
    687.40/1,031.42 = 276.84/x
  3. Step 3: Cross multiply
    687.40x = 1,031.42 × 276.84
  4. Step 4: Simplify right side
    687.40x = 285,539.00
  5. Step 5: Solve for x
    x = 285,539.00/687.40
  6. Step 6: Final answer
    x = 415.39

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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.