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Finding the Fourth Proportional to 278.47, 384.21 and 189.79

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Solution

The fourth proportional to 278.47, 384.21 and 189.79 is: 261.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.47 : 384.21 = 189.79 : x
  2. Step 2: Convert to fraction form
    278.47/384.21 = 189.79/x
  3. Step 3: Cross multiply
    278.47x = 384.21 × 189.79
  4. Step 4: Simplify right side
    278.47x = 72,918.26
  5. Step 5: Solve for x
    x = 72,918.26/278.47
  6. Step 6: Final answer
    x = 261.86

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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.