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Finding the Fourth Proportional to 438.12, 654.72 and 321.78

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Solution

The fourth proportional to 438.12, 654.72 and 321.78 is: 480.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    438.12 : 654.72 = 321.78 : x
  2. Step 2: Convert to fraction form
    438.12/654.72 = 321.78/x
  3. Step 3: Cross multiply
    438.12x = 654.72 × 321.78
  4. Step 4: Simplify right side
    438.12x = 210,675.80
  5. Step 5: Solve for x
    x = 210,675.80/438.12
  6. Step 6: Final answer
    x = 480.86

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.