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Finding the Fourth Proportional to 261.20, 391.81 and 215.46

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Solution

The fourth proportional to 261.20, 391.81 and 215.46 is: 323.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.20 : 391.81 = 215.46 : x
  2. Step 2: Convert to fraction form
    261.20/391.81 = 215.46/x
  3. Step 3: Cross multiply
    261.20x = 391.81 × 215.46
  4. Step 4: Simplify right side
    261.20x = 84,419.82
  5. Step 5: Solve for x
    x = 84,419.82/261.20
  6. Step 6: Final answer
    x = 323.20

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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.