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Finding the Fourth Proportional to 279.12, 385.20 and 210

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Solution

The fourth proportional to 279.12, 385.20 and 210 is: 289.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.12 : 385.20 = 210 : x
  2. Step 2: Convert to fraction form
    279.12/385.20 = 210/x
  3. Step 3: Cross multiply
    279.12x = 385.20 × 210
  4. Step 4: Simplify right side
    279.12x = 80,892
  5. Step 5: Solve for x
    x = 80,892/279.12
  6. Step 6: Final answer
    x = 289.81

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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.