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Finding the Fourth Proportional to 642.12, 885.45 and 476.65

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Solution

The fourth proportional to 642.12, 885.45 and 476.65 is: 657.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.12 : 885.45 = 476.65 : x
  2. Step 2: Convert to fraction form
    642.12/885.45 = 476.65/x
  3. Step 3: Cross multiply
    642.12x = 885.45 × 476.65
  4. Step 4: Simplify right side
    642.12x = 422,049.74
  5. Step 5: Solve for x
    x = 422,049.74/642.12
  6. Step 6: Final answer
    x = 657.28

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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.