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Finding the Fourth Proportional to 643.79, 964.76 and 318.78

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Solution

The fourth proportional to 643.79, 964.76 and 318.78 is: 477.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.79 : 964.76 = 318.78 : x
  2. Step 2: Convert to fraction form
    643.79/964.76 = 318.78/x
  3. Step 3: Cross multiply
    643.79x = 964.76 × 318.78
  4. Step 4: Simplify right side
    643.79x = 307,544.60
  5. Step 5: Solve for x
    x = 307,544.60/643.79
  6. Step 6: Final answer
    x = 477.71

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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.