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Finding the Fourth Proportional to 861.28, 1,291.97 and 212.02

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Solution

The fourth proportional to 861.28, 1,291.97 and 212.02 is: 318.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.28 : 1,291.97 = 212.02 : x
  2. Step 2: Convert to fraction form
    861.28/1,291.97 = 212.02/x
  3. Step 3: Cross multiply
    861.28x = 1,291.97 × 212.02
  4. Step 4: Simplify right side
    861.28x = 273,923.48
  5. Step 5: Solve for x
    x = 273,923.48/861.28
  6. Step 6: Final answer
    x = 318.04

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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.