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Finding the Fourth Proportional to 1,125, 1,687.24 and 431.42

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Solution

The fourth proportional to 1,125, 1,687.24 and 431.42 is: 647.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,125 : 1,687.24 = 431.42 : x
  2. Step 2: Convert to fraction form
    1,125/1,687.24 = 431.42/x
  3. Step 3: Cross multiply
    1,125x = 1,687.24 × 431.42
  4. Step 4: Simplify right side
    1,125x = 727,909.08
  5. Step 5: Solve for x
    x = 727,909.08/1,125
  6. Step 6: Final answer
    x = 647.03

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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.