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Finding the Fourth Proportional to 421.20, 630.79 and 318.33

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Solution

The fourth proportional to 421.20, 630.79 and 318.33 is: 476.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.20 : 630.79 = 318.33 : x
  2. Step 2: Convert to fraction form
    421.20/630.79 = 318.33/x
  3. Step 3: Cross multiply
    421.20x = 630.79 × 318.33
  4. Step 4: Simplify right side
    421.20x = 200,798.58
  5. Step 5: Solve for x
    x = 200,798.58/421.20
  6. Step 6: Final answer
    x = 476.73

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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.