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Finding the Fourth Proportional to 427.20, 639.78 and 324.36

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Solution

The fourth proportional to 427.20, 639.78 and 324.36 is: 485.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.20 : 639.78 = 324.36 : x
  2. Step 2: Convert to fraction form
    427.20/639.78 = 324.36/x
  3. Step 3: Cross multiply
    427.20x = 639.78 × 324.36
  4. Step 4: Simplify right side
    427.20x = 207,519.04
  5. Step 5: Solve for x
    x = 207,519.04/427.20
  6. Step 6: Final answer
    x = 485.77

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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.