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Finding the Fourth Proportional to 431.20, 646.76 and 142.64

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Solution

The fourth proportional to 431.20, 646.76 and 142.64 is: 213.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.20 : 646.76 = 142.64 : x
  2. Step 2: Convert to fraction form
    431.20/646.76 = 142.64/x
  3. Step 3: Cross multiply
    431.20x = 646.76 × 142.64
  4. Step 4: Simplify right side
    431.20x = 92,253.85
  5. Step 5: Solve for x
    x = 92,253.85/431.20
  6. Step 6: Final answer
    x = 213.95

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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.