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Finding the Fourth Proportional to 1,428.24, 2,142.36 and 812

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Solution

The fourth proportional to 1,428.24, 2,142.36 and 812 is: 1,218

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.24 : 2,142.36 = 812 : x
  2. Step 2: Convert to fraction form
    1,428.24/2,142.36 = 812/x
  3. Step 3: Cross multiply
    1,428.24x = 2,142.36 × 812
  4. Step 4: Simplify right side
    1,428.24x = 1,739,596.32
  5. Step 5: Solve for x
    x = 1,739,596.32/1,428.24
  6. Step 6: Final answer
    x = 1,218

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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.