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Finding the Fourth Proportional to 261.19, 391.79 and 68.81

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Solution

The fourth proportional to 261.19, 391.79 and 68.81 is: 103.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.19 : 391.79 = 68.81 : x
  2. Step 2: Convert to fraction form
    261.19/391.79 = 68.81/x
  3. Step 3: Cross multiply
    261.19x = 391.79 × 68.81
  4. Step 4: Simplify right side
    261.19x = 26,960.22
  5. Step 5: Solve for x
    x = 26,960.22/261.19
  6. Step 6: Final answer
    x = 103.22

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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.