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Finding the Fourth Proportional to 215.31, 321.35 and 206.40

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Solution

The fourth proportional to 215.31, 321.35 and 206.40 is: 308.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.31 : 321.35 = 206.40 : x
  2. Step 2: Convert to fraction form
    215.31/321.35 = 206.40/x
  3. Step 3: Cross multiply
    215.31x = 321.35 × 206.40
  4. Step 4: Simplify right side
    215.31x = 66,325.61
  5. Step 5: Solve for x
    x = 66,325.61/215.31
  6. Step 6: Final answer
    x = 308.05

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.