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Finding the Fourth Proportional to 1,428.71, 2,142.55 and 648.05

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Solution

The fourth proportional to 1,428.71, 2,142.55 and 648.05 is: 971.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.71 : 2,142.55 = 648.05 : x
  2. Step 2: Convert to fraction form
    1,428.71/2,142.55 = 648.05/x
  3. Step 3: Cross multiply
    1,428.71x = 2,142.55 × 648.05
  4. Step 4: Simplify right side
    1,428.71x = 1,388,481.68
  5. Step 5: Solve for x
    x = 1,388,481.68/1,428.71
  6. Step 6: Final answer
    x = 971.85

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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.