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Finding the Fourth Proportional to 642.69, 885.38 and 611.42

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Solution

The fourth proportional to 642.69, 885.38 and 611.42 is: 842.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.69 : 885.38 = 611.42 : x
  2. Step 2: Convert to fraction form
    642.69/885.38 = 611.42/x
  3. Step 3: Cross multiply
    642.69x = 885.38 × 611.42
  4. Step 4: Simplify right side
    642.69x = 541,339.04
  5. Step 5: Solve for x
    x = 541,339.04/642.69
  6. Step 6: Final answer
    x = 842.30

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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.