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Finding the Fourth Proportional to 428.13, 638.67 and 398.67

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Solution

The fourth proportional to 428.13, 638.67 and 398.67 is: 594.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.13 : 638.67 = 398.67 : x
  2. Step 2: Convert to fraction form
    428.13/638.67 = 398.67/x
  3. Step 3: Cross multiply
    428.13x = 638.67 × 398.67
  4. Step 4: Simplify right side
    428.13x = 254,618.57
  5. Step 5: Solve for x
    x = 254,618.57/428.13
  6. Step 6: Final answer
    x = 594.72

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.