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Finding the Fourth Proportional to 890.48, 1,229.09 and 642.51

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Solution

The fourth proportional to 890.48, 1,229.09 and 642.51 is: 886.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    890.48 : 1,229.09 = 642.51 : x
  2. Step 2: Convert to fraction form
    890.48/1,229.09 = 642.51/x
  3. Step 3: Cross multiply
    890.48x = 1,229.09 × 642.51
  4. Step 4: Simplify right side
    890.48x = 789,699.40
  5. Step 5: Solve for x
    x = 789,699.40/890.48
  6. Step 6: Final answer
    x = 886.83

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.