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Finding the Fourth Proportional to 311.51, 429.36 and 285.36

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Solution

The fourth proportional to 311.51, 429.36 and 285.36 is: 393.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.51 : 429.36 = 285.36 : x
  2. Step 2: Convert to fraction form
    311.51/429.36 = 285.36/x
  3. Step 3: Cross multiply
    311.51x = 429.36 × 285.36
  4. Step 4: Simplify right side
    311.51x = 122,522.17
  5. Step 5: Solve for x
    x = 122,522.17/311.51
  6. Step 6: Final answer
    x = 393.32

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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.