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Finding the Fourth Proportional to 676.10, 1,012.80 and 387.20

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Solution

The fourth proportional to 676.10, 1,012.80 and 387.20 is: 580.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    676.10 : 1,012.80 = 387.20 : x
  2. Step 2: Convert to fraction form
    676.10/1,012.80 = 387.20/x
  3. Step 3: Cross multiply
    676.10x = 1,012.80 × 387.20
  4. Step 4: Simplify right side
    676.10x = 392,156.16
  5. Step 5: Solve for x
    x = 392,156.16/676.10
  6. Step 6: Final answer
    x = 580.03

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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.