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Finding the Fourth Proportional to 642.68, 963.90 and 209.84

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Solution

The fourth proportional to 642.68, 963.90 and 209.84 is: 314.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.68 : 963.90 = 209.84 : x
  2. Step 2: Convert to fraction form
    642.68/963.90 = 209.84/x
  3. Step 3: Cross multiply
    642.68x = 963.90 × 209.84
  4. Step 4: Simplify right side
    642.68x = 202,265.38
  5. Step 5: Solve for x
    x = 202,265.38/642.68
  6. Step 6: Final answer
    x = 314.72

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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.