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Finding the Fourth Proportional to 425.80, 638.70 and 380.20

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Solution

The fourth proportional to 425.80, 638.70 and 380.20 is: 570.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.80 : 638.70 = 380.20 : x
  2. Step 2: Convert to fraction form
    425.80/638.70 = 380.20/x
  3. Step 3: Cross multiply
    425.80x = 638.70 × 380.20
  4. Step 4: Simplify right side
    425.80x = 242,833.74
  5. Step 5: Solve for x
    x = 242,833.74/425.80
  6. Step 6: Final answer
    x = 570.30

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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.