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Finding the Fourth Proportional to 642.69, 964.17 and 209.81

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Solution

The fourth proportional to 642.69, 964.17 and 209.81 is: 314.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.69 : 964.17 = 209.81 : x
  2. Step 2: Convert to fraction form
    642.69/964.17 = 209.81/x
  3. Step 3: Cross multiply
    642.69x = 964.17 × 209.81
  4. Step 4: Simplify right side
    642.69x = 202,294.92
  5. Step 5: Solve for x
    x = 202,294.92/642.69
  6. Step 6: Final answer
    x = 314.76

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.