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Finding the Fourth Proportional to 428.82, 642.20 and 282.12

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Solution

The fourth proportional to 428.82, 642.20 and 282.12 is: 422.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.82 : 642.20 = 282.12 : x
  2. Step 2: Convert to fraction form
    428.82/642.20 = 282.12/x
  3. Step 3: Cross multiply
    428.82x = 642.20 × 282.12
  4. Step 4: Simplify right side
    428.82x = 181,176.05
  5. Step 5: Solve for x
    x = 181,176.05/428.82
  6. Step 6: Final answer
    x = 422.50

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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.