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Finding the Fourth Proportional to 320.76, 442.80 and 287.91

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Solution

The fourth proportional to 320.76, 442.80 and 287.91 is: 397.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    320.76 : 442.80 = 287.91 : x
  2. Step 2: Convert to fraction form
    320.76/442.80 = 287.91/x
  3. Step 3: Cross multiply
    320.76x = 442.80 × 287.91
  4. Step 4: Simplify right side
    320.76x = 127,486.55
  5. Step 5: Solve for x
    x = 127,486.55/320.76
  6. Step 6: Final answer
    x = 397.45

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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.