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Finding the Fourth Proportional to 311.79, 429.96 and 212.28

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Solution

The fourth proportional to 311.79, 429.96 and 212.28 is: 292.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.79 : 429.96 = 212.28 : x
  2. Step 2: Convert to fraction form
    311.79/429.96 = 212.28/x
  3. Step 3: Cross multiply
    311.79x = 429.96 × 212.28
  4. Step 4: Simplify right side
    311.79x = 91,271.91
  5. Step 5: Solve for x
    x = 91,271.91/311.79
  6. Step 6: Final answer
    x = 292.74

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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.