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Finding the Fourth Proportional to 642.20, 885.20 and 455.27

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Solution

The fourth proportional to 642.20, 885.20 and 455.27 is: 627.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.20 : 885.20 = 455.27 : x
  2. Step 2: Convert to fraction form
    642.20/885.20 = 455.27/x
  3. Step 3: Cross multiply
    642.20x = 885.20 × 455.27
  4. Step 4: Simplify right side
    642.20x = 402,998.30
  5. Step 5: Solve for x
    x = 402,998.30/642.20
  6. Step 6: Final answer
    x = 627.53

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.