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Finding the Fourth Proportional to 485.81, 729.20 and 212.09

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Solution

The fourth proportional to 485.81, 729.20 and 212.09 is: 318.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.81 : 729.20 = 212.09 : x
  2. Step 2: Convert to fraction form
    485.81/729.20 = 212.09/x
  3. Step 3: Cross multiply
    485.81x = 729.20 × 212.09
  4. Step 4: Simplify right side
    485.81x = 154,654.97
  5. Step 5: Solve for x
    x = 154,654.97/485.81
  6. Step 6: Final answer
    x = 318.34

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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.