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Finding the Fourth Proportional to 487.38, 672.39 and 312.72

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Solution

The fourth proportional to 487.38, 672.39 and 312.72 is: 431.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    487.38 : 672.39 = 312.72 : x
  2. Step 2: Convert to fraction form
    487.38/672.39 = 312.72/x
  3. Step 3: Cross multiply
    487.38x = 672.39 × 312.72
  4. Step 4: Simplify right side
    487.38x = 210,269.80
  5. Step 5: Solve for x
    x = 210,269.80/487.38
  6. Step 6: Final answer
    x = 431.43

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.