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Finding the Fourth Proportional to 878.85, 1,211.36 and 668.79

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Solution

The fourth proportional to 878.85, 1,211.36 and 668.79 is: 921.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.85 : 1,211.36 = 668.79 : x
  2. Step 2: Convert to fraction form
    878.85/1,211.36 = 668.79/x
  3. Step 3: Cross multiply
    878.85x = 1,211.36 × 668.79
  4. Step 4: Simplify right side
    878.85x = 810,142.11
  5. Step 5: Solve for x
    x = 810,142.11/878.85
  6. Step 6: Final answer
    x = 921.82

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.