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Finding the Fourth Proportional to 643.40, 964.86 and 426.68

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Solution

The fourth proportional to 643.40, 964.86 and 426.68 is: 639.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.40 : 964.86 = 426.68 : x
  2. Step 2: Convert to fraction form
    643.40/964.86 = 426.68/x
  3. Step 3: Cross multiply
    643.40x = 964.86 × 426.68
  4. Step 4: Simplify right side
    643.40x = 411,686.46
  5. Step 5: Solve for x
    x = 411,686.46/643.40
  6. Step 6: Final answer
    x = 639.86

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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.