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Finding the Fourth Proportional to 1,211.89, 1,672.43 and 680.89

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Solution

The fourth proportional to 1,211.89, 1,672.43 and 680.89 is: 939.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,211.89 : 1,672.43 = 680.89 : x
  2. Step 2: Convert to fraction form
    1,211.89/1,672.43 = 680.89/x
  3. Step 3: Cross multiply
    1,211.89x = 1,672.43 × 680.89
  4. Step 4: Simplify right side
    1,211.89x = 1,138,740.86
  5. Step 5: Solve for x
    x = 1,138,740.86/1,211.89
  6. Step 6: Final answer
    x = 939.64

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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.