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Finding the Fourth Proportional to 428.11, 641.44 and 305.76

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Solution

The fourth proportional to 428.11, 641.44 and 305.76 is: 458.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.11 : 641.44 = 305.76 : x
  2. Step 2: Convert to fraction form
    428.11/641.44 = 305.76/x
  3. Step 3: Cross multiply
    428.11x = 641.44 × 305.76
  4. Step 4: Simplify right side
    428.11x = 196,126.69
  5. Step 5: Solve for x
    x = 196,126.69/428.11
  6. Step 6: Final answer
    x = 458.12

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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.