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Finding the Fourth Proportional to 279.78, 419.67 and 87.42

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Solution

The fourth proportional to 279.78, 419.67 and 87.42 is: 131.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.78 : 419.67 = 87.42 : x
  2. Step 2: Convert to fraction form
    279.78/419.67 = 87.42/x
  3. Step 3: Cross multiply
    279.78x = 419.67 × 87.42
  4. Step 4: Simplify right side
    279.78x = 36,687.55
  5. Step 5: Solve for x
    x = 36,687.55/279.78
  6. Step 6: Final answer
    x = 131.13

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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.