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Finding the Fourth Proportional to 279.12, 418.32 and 142.20

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Solution

The fourth proportional to 279.12, 418.32 and 142.20 is: 213.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.12 : 418.32 = 142.20 : x
  2. Step 2: Convert to fraction form
    279.12/418.32 = 142.20/x
  3. Step 3: Cross multiply
    279.12x = 418.32 × 142.20
  4. Step 4: Simplify right side
    279.12x = 59,485.10
  5. Step 5: Solve for x
    x = 59,485.10/279.12
  6. Step 6: Final answer
    x = 213.12

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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.