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Finding the Fourth Proportional to 642.48, 963.84 and 209.76

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Solution

The fourth proportional to 642.48, 963.84 and 209.76 is: 314.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.48 : 963.84 = 209.76 : x
  2. Step 2: Convert to fraction form
    642.48/963.84 = 209.76/x
  3. Step 3: Cross multiply
    642.48x = 963.84 × 209.76
  4. Step 4: Simplify right side
    642.48x = 202,175.08
  5. Step 5: Solve for x
    x = 202,175.08/642.48
  6. Step 6: Final answer
    x = 314.68

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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.