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Finding the Fourth Proportional to 643.41, 964.17 and 438.21

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Solution

The fourth proportional to 643.41, 964.17 and 438.21 is: 656.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.41 : 964.17 = 438.21 : x
  2. Step 2: Convert to fraction form
    643.41/964.17 = 438.21/x
  3. Step 3: Cross multiply
    643.41x = 964.17 × 438.21
  4. Step 4: Simplify right side
    643.41x = 422,508.94
  5. Step 5: Solve for x
    x = 422,508.94/643.41
  6. Step 6: Final answer
    x = 656.67

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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.