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Finding the Fourth Proportional to 428.62, 643.22 and 266.39

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Solution

The fourth proportional to 428.62, 643.22 and 266.39 is: 399.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.62 : 643.22 = 266.39 : x
  2. Step 2: Convert to fraction form
    428.62/643.22 = 266.39/x
  3. Step 3: Cross multiply
    428.62x = 643.22 × 266.39
  4. Step 4: Simplify right side
    428.62x = 171,347.38
  5. Step 5: Solve for x
    x = 171,347.38/428.62
  6. Step 6: Final answer
    x = 399.77

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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.