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Finding the Fourth Proportional to 644.42, 966.90 and 319.70

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Solution

The fourth proportional to 644.42, 966.90 and 319.70 is: 479.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.42 : 966.90 = 319.70 : x
  2. Step 2: Convert to fraction form
    644.42/966.90 = 319.70/x
  3. Step 3: Cross multiply
    644.42x = 966.90 × 319.70
  4. Step 4: Simplify right side
    644.42x = 309,117.93
  5. Step 5: Solve for x
    x = 309,117.93/644.42
  6. Step 6: Final answer
    x = 479.68

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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.