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Finding the Fourth Proportional to 642.48, 885.72 and 455.90

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Solution

The fourth proportional to 642.48, 885.72 and 455.90 is: 628.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.48 : 885.72 = 455.90 : x
  2. Step 2: Convert to fraction form
    642.48/885.72 = 455.90/x
  3. Step 3: Cross multiply
    642.48x = 885.72 × 455.90
  4. Step 4: Simplify right side
    642.48x = 403,800.98
  5. Step 5: Solve for x
    x = 403,800.98/642.48
  6. Step 6: Final answer
    x = 628.50

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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.