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Finding the Fourth Proportional to 428.06, 645.51 and 422.28

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Solution

The fourth proportional to 428.06, 645.51 and 422.28 is: 636.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.06 : 645.51 = 422.28 : x
  2. Step 2: Convert to fraction form
    428.06/645.51 = 422.28/x
  3. Step 3: Cross multiply
    428.06x = 645.51 × 422.28
  4. Step 4: Simplify right side
    428.06x = 272,585.96
  5. Step 5: Solve for x
    x = 272,585.96/428.06
  6. Step 6: Final answer
    x = 636.79

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.