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Finding the Fourth Proportional to 422.40, 583.20 and 311.88

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Solution

The fourth proportional to 422.40, 583.20 and 311.88 is: 430.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    422.40 : 583.20 = 311.88 : x
  2. Step 2: Convert to fraction form
    422.40/583.20 = 311.88/x
  3. Step 3: Cross multiply
    422.40x = 583.20 × 311.88
  4. Step 4: Simplify right side
    422.40x = 181,888.42
  5. Step 5: Solve for x
    x = 181,888.42/422.40
  6. Step 6: Final answer
    x = 430.61

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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.