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Finding the Fourth Proportional to 642.66, 964.14 and 209.85

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Solution

The fourth proportional to 642.66, 964.14 and 209.85 is: 314.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.66 : 964.14 = 209.85 : x
  2. Step 2: Convert to fraction form
    642.66/964.14 = 209.85/x
  3. Step 3: Cross multiply
    642.66x = 964.14 × 209.85
  4. Step 4: Simplify right side
    642.66x = 202,324.78
  5. Step 5: Solve for x
    x = 202,324.78/642.66
  6. Step 6: Final answer
    x = 314.82

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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.