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Finding the Fourth Proportional to 642.12, 963.84 and 639.84

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Solution

The fourth proportional to 642.12, 963.84 and 639.84 is: 960.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.12 : 963.84 = 639.84 : x
  2. Step 2: Convert to fraction form
    642.12/963.84 = 639.84/x
  3. Step 3: Cross multiply
    642.12x = 963.84 × 639.84
  4. Step 4: Simplify right side
    642.12x = 616,703.39
  5. Step 5: Solve for x
    x = 616,703.39/642.12
  6. Step 6: Final answer
    x = 960.42

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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.