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Finding the Fourth Proportional to 425.20, 637.80 and 279.40

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Solution

The fourth proportional to 425.20, 637.80 and 279.40 is: 419.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.20 : 637.80 = 279.40 : x
  2. Step 2: Convert to fraction form
    425.20/637.80 = 279.40/x
  3. Step 3: Cross multiply
    425.20x = 637.80 × 279.40
  4. Step 4: Simplify right side
    425.20x = 178,201.32
  5. Step 5: Solve for x
    x = 178,201.32/425.20
  6. Step 6: Final answer
    x = 419.10

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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.