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Finding the Fourth Proportional to 422.20, 582.30 and 312.40

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Solution

The fourth proportional to 422.20, 582.30 and 312.40 is: 430.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    422.20 : 582.30 = 312.40 : x
  2. Step 2: Convert to fraction form
    422.20/582.30 = 312.40/x
  3. Step 3: Cross multiply
    422.20x = 582.30 × 312.40
  4. Step 4: Simplify right side
    422.20x = 181,910.52
  5. Step 5: Solve for x
    x = 181,910.52/422.20
  6. Step 6: Final answer
    x = 430.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.