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Finding the Fourth Proportional to 687.53, 1,031.81 and 427.92

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Solution

The fourth proportional to 687.53, 1,031.81 and 427.92 is: 642.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.53 : 1,031.81 = 427.92 : x
  2. Step 2: Convert to fraction form
    687.53/1,031.81 = 427.92/x
  3. Step 3: Cross multiply
    687.53x = 1,031.81 × 427.92
  4. Step 4: Simplify right side
    687.53x = 441,524.84
  5. Step 5: Solve for x
    x = 441,524.84/687.53
  6. Step 6: Final answer
    x = 642.19

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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.