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Finding the Fourth Proportional to 428.66, 642.97 and 120.53

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Solution

The fourth proportional to 428.66, 642.97 and 120.53 is: 180.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.66 : 642.97 = 120.53 : x
  2. Step 2: Convert to fraction form
    428.66/642.97 = 120.53/x
  3. Step 3: Cross multiply
    428.66x = 642.97 × 120.53
  4. Step 4: Simplify right side
    428.66x = 77,493.36
  5. Step 5: Solve for x
    x = 77,493.36/428.66
  6. Step 6: Final answer
    x = 180.78

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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.