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Finding the Fourth Proportional to 2,142.28, 3,212.26 and 987

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Solution

The fourth proportional to 2,142.28, 3,212.26 and 987 is: 1,479.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,142.28 : 3,212.26 = 987 : x
  2. Step 2: Convert to fraction form
    2,142.28/3,212.26 = 987/x
  3. Step 3: Cross multiply
    2,142.28x = 3,212.26 × 987
  4. Step 4: Simplify right side
    2,142.28x = 3,170,500.62
  5. Step 5: Solve for x
    x = 3,170,500.62/2,142.28
  6. Step 6: Final answer
    x = 1,479.97

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1.5x scale

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.