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Finding the Fourth Proportional to 1,427.87, 2,142.27 and 647.78

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Solution

The fourth proportional to 1,427.87, 2,142.27 and 647.78 is: 971.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,427.87 : 2,142.27 = 647.78 : x
  2. Step 2: Convert to fraction form
    1,427.87/2,142.27 = 647.78/x
  3. Step 3: Cross multiply
    1,427.87x = 2,142.27 × 647.78
  4. Step 4: Simplify right side
    1,427.87x = 1,387,719.66
  5. Step 5: Solve for x
    x = 1,387,719.66/1,427.87
  6. Step 6: Final answer
    x = 971.88

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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.