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Finding the Fourth Proportional to 2,140.78, 3,211.49 and 659.69

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Solution

The fourth proportional to 2,140.78, 3,211.49 and 659.69 is: 989.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,140.78 : 3,211.49 = 659.69 : x
  2. Step 2: Convert to fraction form
    2,140.78/3,211.49 = 659.69/x
  3. Step 3: Cross multiply
    2,140.78x = 3,211.49 × 659.69
  4. Step 4: Simplify right side
    2,140.78x = 2,118,592.57
  5. Step 5: Solve for x
    x = 2,118,592.57/2,140.78
  6. Step 6: Final answer
    x = 989.64

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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.