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Finding the Fourth Proportional to 724.78, 1,087.17 and 211.78

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Solution

The fourth proportional to 724.78, 1,087.17 and 211.78 is: 317.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    724.78 : 1,087.17 = 211.78 : x
  2. Step 2: Convert to fraction form
    724.78/1,087.17 = 211.78/x
  3. Step 3: Cross multiply
    724.78x = 1,087.17 × 211.78
  4. Step 4: Simplify right side
    724.78x = 230,242.62
  5. Step 5: Solve for x
    x = 230,242.62/724.78
  6. Step 6: Final answer
    x = 317.67

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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.