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Finding the Fourth Proportional to 261, 391.50 and 68.64

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Solution

The fourth proportional to 261, 391.50 and 68.64 is: 102.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    261 : 391.50 = 68.64 : x
  2. Step 2: Convert to fraction form
    261/391.50 = 68.64/x
  3. Step 3: Cross multiply
    261x = 391.50 × 68.64
  4. Step 4: Simplify right side
    261x = 26,872.56
  5. Step 5: Solve for x
    x = 26,872.56/261
  6. Step 6: Final answer
    x = 102.96

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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.