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Finding the Fourth Proportional to 643.76, 964.62 and 438.74

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Solution

The fourth proportional to 643.76, 964.62 and 438.74 is: 657.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.76 : 964.62 = 438.74 : x
  2. Step 2: Convert to fraction form
    643.76/964.62 = 438.74/x
  3. Step 3: Cross multiply
    643.76x = 964.62 × 438.74
  4. Step 4: Simplify right side
    643.76x = 423,217.38
  5. Step 5: Solve for x
    x = 423,217.38/643.76
  6. Step 6: Final answer
    x = 657.41

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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.