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Finding the Fourth Proportional to 311.28, 429.48 and 288

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Solution

The fourth proportional to 311.28, 429.48 and 288 is: 397.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.28 : 429.48 = 288 : x
  2. Step 2: Convert to fraction form
    311.28/429.48 = 288/x
  3. Step 3: Cross multiply
    311.28x = 429.48 × 288
  4. Step 4: Simplify right side
    311.28x = 123,690.24
  5. Step 5: Solve for x
    x = 123,690.24/311.28
  6. Step 6: Final answer
    x = 397.36

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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.