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Finding the Fourth Proportional to 878.21, 1,317.47 and 261.89

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Solution

The fourth proportional to 878.21, 1,317.47 and 261.89 is: 392.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.21 : 1,317.47 = 261.89 : x
  2. Step 2: Convert to fraction form
    878.21/1,317.47 = 261.89/x
  3. Step 3: Cross multiply
    878.21x = 1,317.47 × 261.89
  4. Step 4: Simplify right side
    878.21x = 345,024.32
  5. Step 5: Solve for x
    x = 345,024.32/878.21
  6. Step 6: Final answer
    x = 392.87

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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.