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Finding the Fourth Proportional to 642.31, 885.43 and 455.23

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Solution

The fourth proportional to 642.31, 885.43 and 455.23 is: 627.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.31 : 885.43 = 455.23 : x
  2. Step 2: Convert to fraction form
    642.31/885.43 = 455.23/x
  3. Step 3: Cross multiply
    642.31x = 885.43 × 455.23
  4. Step 4: Simplify right side
    642.31x = 403,074.30
  5. Step 5: Solve for x
    x = 403,074.30/642.31
  6. Step 6: Final answer
    x = 627.54

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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.