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Finding the Fourth Proportional to 672.18, 1,005.86 and 487.30

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Solution

The fourth proportional to 672.18, 1,005.86 and 487.30 is: 729.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    672.18 : 1,005.86 = 487.30 : x
  2. Step 2: Convert to fraction form
    672.18/1,005.86 = 487.30/x
  3. Step 3: Cross multiply
    672.18x = 1,005.86 × 487.30
  4. Step 4: Simplify right side
    672.18x = 490,149.94
  5. Step 5: Solve for x
    x = 490,149.94/672.18
  6. Step 6: Final answer
    x = 729.20

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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.