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Finding the Fourth Proportional to 261.81, 391.17 and 198.86

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Solution

The fourth proportional to 261.81, 391.17 and 198.86 is: 297.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.81 : 391.17 = 198.86 : x
  2. Step 2: Convert to fraction form
    261.81/391.17 = 198.86/x
  3. Step 3: Cross multiply
    261.81x = 391.17 × 198.86
  4. Step 4: Simplify right side
    261.81x = 77,786.11
  5. Step 5: Solve for x
    x = 77,786.11/261.81
  6. Step 6: Final answer
    x = 297.11

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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.