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Finding the Fourth Proportional to 320.58, 439.68 and 311.28

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Solution

The fourth proportional to 320.58, 439.68 and 311.28 is: 426.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    320.58 : 439.68 = 311.28 : x
  2. Step 2: Convert to fraction form
    320.58/439.68 = 311.28/x
  3. Step 3: Cross multiply
    320.58x = 439.68 × 311.28
  4. Step 4: Simplify right side
    320.58x = 136,863.59
  5. Step 5: Solve for x
    x = 136,863.59/320.58
  6. Step 6: Final answer
    x = 426.92

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.