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Finding the Fourth Proportional to 428.79, 643.17 and 181.92

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Solution

The fourth proportional to 428.79, 643.17 and 181.92 is: 272.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.79 : 643.17 = 181.92 : x
  2. Step 2: Convert to fraction form
    428.79/643.17 = 181.92/x
  3. Step 3: Cross multiply
    428.79x = 643.17 × 181.92
  4. Step 4: Simplify right side
    428.79x = 117,005.49
  5. Step 5: Solve for x
    x = 117,005.49/428.79
  6. Step 6: Final answer
    x = 272.87

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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.