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Finding the Fourth Proportional to 644.40, 965.64 and 319.80

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Solution

The fourth proportional to 644.40, 965.64 and 319.80 is: 479.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.40 : 965.64 = 319.80 : x
  2. Step 2: Convert to fraction form
    644.40/965.64 = 319.80/x
  3. Step 3: Cross multiply
    644.40x = 965.64 × 319.80
  4. Step 4: Simplify right side
    644.40x = 308,811.67
  5. Step 5: Solve for x
    x = 308,811.67/644.40
  6. Step 6: Final answer
    x = 479.22

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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.