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Finding the Fourth Proportional to 279.98, 420.78 and 135.80

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Solution

The fourth proportional to 279.98, 420.78 and 135.80 is: 204.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.98 : 420.78 = 135.80 : x
  2. Step 2: Convert to fraction form
    279.98/420.78 = 135.80/x
  3. Step 3: Cross multiply
    279.98x = 420.78 × 135.80
  4. Step 4: Simplify right side
    279.98x = 57,141.92
  5. Step 5: Solve for x
    x = 57,141.92/279.98
  6. Step 6: Final answer
    x = 204.09

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.